The domain for f(x) and g(x) is the set of all real numbers. Let f(x) = 3x + 8 and g(x) = x2. Find (f • g)(x).

A. x2 − 3x − 8
B. 3x2 + 8
C. 3x3 + 3x2 + 8
D. 3x3 + 8x2