Answer:
The correct answer is A.
Step-by-step explanation:
Unbalanced forces change the speed of movement of an object because they act non-uniformly on the object to which they relate. When a child on a bicycle brakes on a stop sign, the brakes act unevenly on the wheel, causing an uneven decrease in speed. In this way, you lose the balance of the movement you had prior to braking.
Have a nice day!