Question $3$

If $x$ and $t$ represent distance and time, respectively, the $C$ in $x=\frac{1}{2}C{t}^3$ must

have the dimensions ML$/$T ${?}^2.$

have the dimensions $M.$

have the dimensions $\frac{L}{T^2}.$

have the dimensions $\frac{L}{T^3}$

be dimensionless.