$\mathrm{v}=\mathrm{A} \omega \cos \omega \mathrm{t} ; \mathrm{a}=\mathrm{A} \omega^{2} \sin \omega \mathrm{t}$
$\Rightarrow \frac{v^{2}}{A^{2} \omega^{2}}+\frac{a^{2}}{A^{2} \omega^{4}}=1$
$(ii)$ and $(iii)$ are correct

$(a)$ Potential energy is always equal to its $K.E.$
$(b)$ Average potential and kinetic energy over any given time interval are always equal.
$(c)$ Sum of the kinetic and potential energy at any point of time is constant.
$(d)$ Average $K.E.$ in one time period is equal to average potential energy in one time period.
Choose the most appropriate option from the options given below:

