\[\begin {array} {1 1} (a)\;\frac{2}{3} mv^2 & \quad (b)\;\bigg(\frac{3}{2}\bigg)mv^2 \\ (c)\;\bigg(\frac{4}{3}\bigg)mv^2 & \quad (d)\;\bigg(\frac{3}{4}\bigg)mv^2 \end {array}\]