A Merry$-$Go$-$Round $($a solid disc$)$ with mass M and radius R is spinning freely with

angular velocity $2\mathrm{.}00$ra$($d$)/($s$).$ A child with mass m$=($M$)/(10)9($R$)/(10)2\mathrm{.}00$ra$($d$)/($s$)$

B$1\mathrm{.}72$ra$($d$)/($s$)$

C$1\mathrm{.}69$ra$($d$)/($s$)$

D$2\mathrm{.}32$ra$($d$)/($s$)$

E$2\mathrm{.}36$ra$($d$)/($s$)$