ANSWER
The correct choice is A.
EXPLANATION
The given cosine function is:
This function has an amplitude of 2.
Hence it must have range,
-2≤f(t)≤2
It has a period of
Hence the function must complete one cycle on the interval,
[0,½π],
[½π,π],
etc.
The negative sign shows a reflection in the y-axis but since the cosine function is even, the function retraces itself.
The correct choice is A