第935题：cosine curve

Consider the function $y=2-3 \cos (x)$ , what effect does the 3 have?

A. Vertical shift of $y=2-\cos(x)$ down 3 units.

B. Vertical stretch of $y=2-\cos(x)$ by a factor of 3.

C. Horizontal shift of $y=2-\cos(x)$  left 3 units.

D. Horizontal shift of $y=2-\cos(x)$  right 3 units.

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