A block of mass m is suspended from one end of a light spring as shown. The origin O is considered at distance equal to natural length of the spring from the ceiling and vertical downwards direction as positive y-axis. When the system is in equilibrium a bullet of mass `(m)/(3)` moving in vertical up wards direction with velocity `v_0` strikes the block and embeds into it. As a result, the block (with bullet embedded into it) moves up and start oscillating. Based on the given information, answer the following question:
Q. The time taken by the block bullet system to move from `y=(mg)/(k)` (initial equilibrium position) to `y=0` (natural length of spring) is (A represents the amplitude of motion)

Options

A. Both the scales will read 10 kg
B. Both the scales will read 20 kg
C. The sum of readings of two balances will be 20 kg
D. None of the above

Answer

B