In the given figure, a solid sphere is placed on a plank having acceleration $a_{0}$ (shown in the figure). Then:
(a). if $a_{p}=a_{0}$, pure rolling takes place
(b) if $v_{p}=v_{0}$ pure rolling takes place
(c) if $a_{p}=a_{0}, v_{p} \neq v_{0}$ pure rolling takes place
(d) if $a_{p}=a_{0}, v_{p}=v_{0}$, pure rolling takes place