The displacement of a particle moving in S.H.M. at any instant is given by $\mathrm{y}=\mathrm{asin\omega t}$. The acceleration after time $\mathrm{t}=\frac{\mathrm{T}}{4}$ is (where T is the time period) 

• A

  $\mathrm{a\omega }$

• B

  $-\mathrm{a\omega }$

• C

  ${\mathrm{a\omega }}^2$

• D

  $-{\mathrm{a\omega }}^2$