A wooden block of mass `10 gm` is dropped from the top of a cliff `100 m` high. Simultaneously a bullet of same mass is fired from the foot of the cliff vertically upwards with a velocity of `100 ms^(-1)`. If the bullet after collision gets embedded in the block, the common velocity of the bullet and the block immediately after collision is `(g=10 ms^(-2))`.
A. `40 ms^(-1)` downward
B. `40 ms^(-1)` upward
C. `80 ms^(-1)` upward
D. zero