Two technicians are discussing master cylinders. Technician A says that it is normal to see fluid movement in the reservoir when the brake pedal is depressed. Technician B says a defective master cylinder can cause the brake pedal to slowly sink to the floor when depressed. Which technician is correct?
a. Technician A only
b. Both Technicians A and B
c. Technician B only
d. Neither Technician A nor B

The best answer is "B"

Both Technician A and B

Explanation:

The master cylinder is a hydraulic pump. As you pump the pedal, it forces the brake fluid into the calipers/wheel cylinders. However, air compresses quite easily, as such the hydraulic pressure reduce the by large amounts because of the presence of air in the braking system.

The two Technicians are both right.

it would be kevlar ^^

the entire statement is true and correct.  

there's no diagram, nothing is illustrated, and no question is asked.