Inelastic Collisions in One Dimension: an 8

Inelastic collisions in one dimension: An 8.0-g bullet is shot into a 4.0-kg block, at rest on a frictionless horizontal surface (see the figure) . The bullet remains lodged in the block. The block moves into an ideal massless spring and compresses it by 8.7 cm. The spring constant of the spring is 2400 N/m. The initial velocity of the bullet is closest to

A) 1100 m/s.
B) 1200 m/s.
C) 900 m/s.
D) 1300 m/s.
E) 1000 m/s.