The correct answer is option 'B': "piston and small end of connecting rod". Let's explain why this is the correct answer in detail:

1. Gudgeon Pin Function:
The gudgeon pin, also known as the piston pin or wrist pin, is a crucial component in an internal combustion engine. It forms the link between the piston and the connecting rod, allowing for the transfer of motion and power from the piston to the connecting rod and ultimately to the crankshaft.

2. Piston and Small End of Connecting Rod:
The piston is a cylindrical component that moves up and down within the cylinder of an engine. It is connected to the connecting rod, which in turn connects to the crankshaft. The small end of the connecting rod is the part that connects to the piston, while the big end connects to the crankshaft.

3. Role of the Gudgeon Pin:
The gudgeon pin is inserted through the small end of the connecting rod and serves as a pivot point for the connecting rod's movement. It is positioned within the piston bosses, which are cylindrical holes in the piston, allowing the piston to articulate freely on the gudgeon pin.

4. Transferring Motion:
As the piston moves up and down within the cylinder, the gudgeon pin ensures that the motion of the piston is transmitted to the connecting rod. The gudgeon pin acts as a link between the piston and the connecting rod, allowing the piston to push and pull the connecting rod as it moves.

5. Importance of Proper Design:
The gudgeon pin must be designed to withstand the forces and pressures generated within the engine. It needs to be strong enough to handle the combustion forces and vibrations while maintaining a precise fit within the piston bosses and connecting rod. Proper lubrication is also crucial to reduce friction and wear between the gudgeon pin and its surrounding components.

In conclusion, the gudgeon pin forms the link between the piston and the small end of the connecting rod in an internal combustion engine. It plays a vital role in transmitting the motion and power from the piston to the connecting rod, allowing for the conversion of linear motion into rotational motion.

The correct answer is option 'B', which states that the gudgeon pin forms the link between the piston and the small end of the connecting rod. Let's understand this in detail:

The gudgeon pin, also known as the wrist pin or piston pin, is a crucial component in an internal combustion engine. It serves as a linkage between the piston and the connecting rod.

1. Function of the gudgeon pin:
The primary function of the gudgeon pin is to connect the piston head to the small end of the connecting rod. It allows the piston to pivot on the gudgeon pin, which translates the reciprocating motion of the piston into rotary motion at the crankshaft.

2. Location of the gudgeon pin:
The gudgeon pin is located inside the piston, passing through the bosses or bosses on the piston's skirt. It is supported by the small end of the connecting rod, which fits tightly around the pin.

3. Connection to the piston:
The gudgeon pin is press-fitted into the bosses on the piston. It must be securely held in place to withstand the forces and temperatures encountered during engine operation. The pin is usually made of hardened steel to provide strength and durability.

4. Connection to the connecting rod:
The small end of the connecting rod has a bore that matches the diameter of the gudgeon pin. The pin fits into this bore, creating a rotational joint between the piston and the connecting rod. The gudgeon pin is usually fixed within the connecting rod using circlips or retaining rings to prevent lateral movement.

5. Function during engine operation:
As the piston moves up and down within the cylinder, the gudgeon pin transfers the reciprocating motion of the piston to the connecting rod. This motion is essential for converting the linear motion of the piston into the rotary motion needed to drive the crankshaft. The gudgeon pin must be able to withstand high loads and pressures while maintaining a smooth movement within the piston and connecting rod.

In conclusion, the gudgeon pin forms the link between the piston and the small end of the connecting rod in an internal combustion engine. It allows for the transfer of motion from the piston to the connecting rod, enabling the conversion of linear motion into rotary motion.