The displacement x with respect to time t of a particle moving in simple harmonic motion is given by x = 5cos(16pi*t). Where x is in mm and t is in seconds. If the particle starts at x = 5mm and t = 0s. At what time t does it first pass through its equilibrium position?

A) 1/32 s

B) 1/16 s

C) 1/5 s

D) 4 s

E) 8 s