An Object Is Moving with Simple Harmonic Motion According to the Equation

Multiple Choice

An object is moving with simple harmonic motion according to the equation $x = ( 5.0 \mathrm {~cm} ) \cos ( 10 \pi t )$ . The time required for the object to move from its initial displacement to 3.5 cm is

A) 15 ms.
B) 25 ms.
C) 1.5 s.
D) 2.5 s.