Explanation:

When discussing gears, the pressure angle refers to the angle between the line of action and the common tangent to the pitch circles of two meshing gears. The pressure angle affects several factors related to gear design and performance.

1. Definition of pressure angle:
The pressure angle is defined as the angle between the direction of the force acting on the gear tooth and the line perpendicular to the tooth surface at the point of contact. It is typically measured in degrees.

2. Effect on gear strength:
The pressure angle has a significant impact on the strength of the gear teeth. A larger pressure angle results in wider gear teeth, which increases the contact area between the meshing gears. This wider base provides better load distribution across the tooth face, resulting in stronger teeth that can withstand higher loads without deformation or failure.

3. Effect on gear size:
A larger pressure angle leads to a wider gear base, which requires a larger gear size. This means that gears with a large pressure angle will have a larger diameter and overall size compared to gears with a smaller pressure angle.

4. Other considerations:
While a larger pressure angle can improve gear strength, there are some trade-offs to consider. Gears with a larger pressure angle may experience increased sliding and friction during operation, which can lead to higher power losses and reduced efficiency. Additionally, larger pressure angles may require modifications to the gear design, such as stronger materials or increased tooth thickness, which can increase the cost and complexity of gear manufacturing.

Conclusion:
In summary, a larger pressure angle in gears results in wider gear teeth, which provide a stronger base and better load distribution. However, it also leads to larger gear size and potential drawbacks such as increased sliding and manufacturing complexities. Hence, option 'B' is the correct answer as it accurately describes the impact of a large pressure angle on gear design.