Correct Answer - B
`x = a cos(omega t +theta)`…(i)
And `v = (dx)/(dt) = - aomegasin(omega t + theta)`…(ii)
Given at `t = 0 , x = 1 cm and v = pi` and `omega = pi`
Putting these value in equation (i) and (ii) , are will get
`sin theta = (-1)/(a)` and `cos theta = (1)/(A)`
`rArr sin^(2) theta + cos^(2) theta = (-(1)/(a))^(2) +((1)/(a))^(2) rArr a = sqrt(2) cm`