Let the function f(x) have the form f(x) = Acos(x-C). To produce a graph that matches the one shown below, what must the value of C be?

Answer: Option B, C = 3.
Step-by-step explanation:
Here we have the function:
f(x) = A*cos(x - C)
A is the amplitude, and we can easily see that the amplitude is 2.
Then:
f(x) = 2*cos(x - C)
We also can see that when x = 0, f(x) ≈ -2
This means that:
cos(0 - C) ≈ -1
Cos(C) ≈ -1
Now we can just evaluate in the different options and see which one is the correct option.
Cos(1) = 0.54
Cos(2) = -0.42
Cos(3) = -0.99
Cos(4) = -0.65
The closer option to -1 is when C = 3, then the correct option is option B.