Answer:
C
Explanation:
What is the greatest value that sin(x) + 1 can have? It isn't 1.
f(90) = sin(90) + 1
f(90) = 1 + 1 = 2
What is the smallest value that sin(x) + 1 can have? It still isn't one.
f(-90) = sin(-90) + 1
f(-90) = -1 + 1 = 0
So the midline is (2 + 0)/2 = 1
y = 1 is the answer.