Which of the Following Is Identical To $\cos (x+y) \cos (x-y)$

Multiple Choice

Which of the following is identical to $\cos (x+y) \cos (x-y)$ ?

A) $\cos ^{2} x y+\sin ^{2} x y$
B) $(\cos x \cos y+\sin x \sin y) ^{2}$
C) $\cos ^{2} x-\sin ^{2} y$
D) $\sin ^{2} x+\cos ^{2} y$