An equation matches the description of the function below.

A cosine curve has a period of 2π, an amplitude of 4, a left phase shift of StartFraction pi Over 2 EndFraction, and a vertical translation down 2 units.

Which equation matches the description?

y = 4 cosine (2 x minus StartFraction pi Over 2 EndFraction) minus 2
y = 4 cosine (2 x + StartFraction pi Over 2 EndFraction) minus 2
y = 4 cosine (x minus StartFraction pi Over 2 EndFraction) minus 2
y = 4 cosine (x + StartFraction pi Over 2 EndFraction) minus 2