A block of mass 100 g attached to a spring of stiffness 100 N/m is lying on a frictionless floor as shown. The block is moved to compress the spring by 10 cm and released. If the collision with the wall is elastic the time ** of motion is
(a) 0.2 *
(b) 0.166 *
(c) 0.155 *
(d) 0.133 *
