Explanation:

A band brake is a type of brake that uses a flexible band or strap to surround and squeeze a rotating drum or disk. It is commonly used in various applications, such as bicycles, motorcycles, and industrial machines.

A simple band brake consists of a flexible band or strap that is wrapped around a drum or disk. One end of the band is attached to a fixed point, while the other end is connected to a lever or mechanism that applies force to the band, causing it to press against the drum or disk and create friction, thereby slowing down or stopping the rotation.

A differential band brake is a variation of the simple band brake that includes a differential mechanism. This mechanism allows for the differential application of force to the two ends of the band, resulting in different levels of braking force on each side. This can be useful in certain applications where differential braking is required, such as in vehicles with differential steering systems.

Comparison:

In both the simple band brake and the differential band brake, at least one end of the band passes through a fulcrum. However, the key difference lies in the number of ends that pass through the fulcrum.

- Simple Band Brake: In a simple band brake, only one end of the band passes through the fulcrum. This end is typically connected to a lever or mechanism that applies force to the band, causing it to tighten around the drum or disk.

- Differential Band Brake: In a differential band brake, both ends of the band pass through the fulcrum. The differential mechanism allows for the differential application of force to the two ends of the band, resulting in different levels of braking force on each side.

Conclusion:

Based on the above explanation, the correct answer is option 'B' - Neither end. In both the simple band brake and the differential band brake, at least one end of the band passes through the fulcrum. However, in the case of the differential band brake, both ends of the band pass through the fulcrum.