Describe the following graph using a cosine function.

$y=3\cos (2x-\frac{\pi }{2})+2$

$y=3\cos (2x-\frac{\pi }{2})-2$

$y=3\cos (2x+\frac{\pi }{2})+2$

$y=3\cos (2x+\frac{\pi }{2})-2$