The correct answer is option 'A' - transverse fillet welded joints are designed for tensile strength.

Transverse fillet welded joints are a type of joint commonly used in structural applications where two pieces of metal are joined together by a fillet weld. The weld is placed perpendicular to the direction of the applied load, hence the term "transverse". These types of joints are commonly used in applications where the primary loading is in tension.

Here is an explanation of why transverse fillet welded joints are designed for tensile strength:

1. Definition of tensile strength:
- Tensile strength refers to the ability of a material or joint to resist pulling forces or tensile stresses without breaking or deforming.
- In the case of a welded joint, tensile strength is a critical design consideration as it determines the load-carrying capacity of the joint in tension.

2. Design considerations for transverse fillet welded joints:
- When designing a transverse fillet welded joint, the main objective is to ensure that the joint can withstand the maximum tensile forces that will be applied to it during its intended use.
- The dimensions of the fillet weld, such as its size, length, and throat thickness, are determined based on the required tensile strength of the joint.
- The size and length of the fillet weld are typically specified in welding codes and standards, which provide guidelines for designing fillet welds for different applications and materials.
- The throat thickness of the fillet weld is an important parameter that affects the tensile strength of the joint. It is the shortest distance between the root and the face of the weld. The throat thickness must be adequate to resist the applied tensile forces without fracture or failure.

3. Load distribution in transverse fillet welded joints:
- In a transverse fillet welded joint, the load is transmitted from one member to another through the fillet weld.
- The fillet weld acts as a load-bearing component and distributes the applied tensile forces across its length.
- The fillet weld undergoes tensile stress along its throat thickness due to the applied load.
- The design of the fillet weld ensures that the tensile stresses in the weld are within the allowable limits for the material and the joint configuration.

In conclusion, transverse fillet welded joints are designed for tensile strength as they are primarily used to withstand tensile forces. The dimensions and configuration of the fillet weld are carefully designed to ensure that the joint can carry the required tensile loads without failure or deformation.