The acceleration of a certain simple harmonic oscillator is given by a $-(15\mathrm{.}8\frac{m}{s^2})cos(2\mathrm{.}51$t$).$ What is the amplitude of the simple harmonic motion?

A$)15\mathrm{.}8$ m

B$)2\mathrm{.}51$ m

C$)11\mathrm{.}1$ m

D$)4\mathrm{.}41$ m

E$)6\mathrm{.}30$ m