The Position of a 0

The position of a 0.64-kg mass undergoing simple harmonic motion is given by x = (0.120 m) cos (πt/16) .What is the maximum net force on the mass as it oscillates?

A) 0.98 × 10−³ N
B) 7.4 × 10−³ N
C) 3.0 × 10−³ N
D) 4.7 N