A 2 kg block slides on a horizontal floor with a speed of 4 m/s. It strikes a uncompressed spring and compresses it till the block is motionless. The kinetic friction force is 15 N and spring constant is 10000 N/m. The spring compresses by
Options:
(a) 5.5 cm
(b) 2.5 cm
(c) 11.0 cm
(d) 8.5 cm