Which graph represents a function with amplitude 4 and period π?
On a coordinate plane, a cosine function has a maximum of 4 and minimum of negative 4. It completes one period at 2 pi.

On a coordinate plane, a cosine function has a maximum of 2 and minimum of negative 2. It completes one period at pi.

On a coordinate plane, a cosine function has a maximum of 2 and minimum of negative 2. It completes one period at 2 pi.

On a coordinate plane, a cosine function has a maximum of 4 and minimum of negative 4. It completes one period at pi.