A particle moves with simple harmonic motion in a straight line. In first \( \tau \mathrm{s} \) , after starting from rest it travels a distance a, and in next \( \tau \) s it travels 2 a , in same direction, then:

A amplitude of motion is 4 a

B time period of oscillations is \( 6 \tau \)

C amplitude of motion is 3 a