Circular motion has to be a complete circle true or false

The answer is false. You don't need to move in a full circle to be going in a circular motion. Apex

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

the answer is a. at the equator