The Motion Is Simple Harmonic with Period T, Write an Equation

Multiple Choice

the motion is simple harmonic with period T, write an equation that relates the displacement d of the object from its rest
position after t seconds. Also assume that the positive direction of the motion is up.An object attached to a coiled spring is pulled down a distance a from its rest position and then released. Assuming that
-a = 5; T = 10 seconds A) $d = 5 \cos ( 10 t )$
B) $d = - 5 \cos ( 10 t )$
$C ) d = - 5 \cos \left( \frac { \pi } { 5 } t \right)$
D) $\mathrm { d } = 5 \cos \left( \frac { \pi } { 5 } \mathrm { t } \right)$