The x-t graph of a particle undergoing simple harmonic motion is shown below. The acceleration of the particle of `t=4//3s` is
A. `(sqrt(3))/(32) pi^(2)cm//s^(2)`
B. `(-pi^(2))/(32)cm//s^(2)`
C. `(pi^(2))/(32)cm//s^(2)`
D. `-(sqrt(3))/(32) pi^(2)cm//s^(2)`