
Sena A. answered 05/02/20
Ivy League Computer Science Graduate, Patient Tutor
If the graph of the derivative of a function f'(x) is decreasing, that means the original graph for f(x) is concave down. Since the graph of f'(x) is decreasing between -1.5 and 1.5, f(x) must be concave down. Hence, Option 3) is correct.