At $30^{\circ} \mathrm{C}$, a lead bullet of $50 \mathrm{~g}$, is fired vertically upwards with a speed of $840 \mathrm{~m} / \mathrm{s}$. The specific heat of lead is $0.02 \mathrm{cal} / \mathrm{g}^{\circ} \mathrm{C}$. On returning to the starting level, it strikes to a cake of ice at $0^{\circ} \mathrm{C}$. The amount of ice melted is:
(Assume all the energy is spent in melting only)
(a) $62.7 \mathrm{~g}$
(b) $55 \mathrm{~g}$
(c) $52.875 \mathrm{~kg}$
(d) $52.875 \mathrm{~g}$