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

Question

( A ) amplitude of motion is 3a
( B ) time period of oscillations is 8 $\tau$
( C ) time period of oscillations is 6 $\tau$
( D ) amplitude of motion is 4a