A Block Is Placed in Oscillation on a Frictionless Horizontal

Multiple Choice

A block is placed in oscillation on a frictionless horizontal surface attached to a spring that is also attached to a wall.If,when stretched away from equilibrium by 15 cm and released,it oscillates with a period of 0.25s,and if the mass of the block is 15 kg,what force was required to stretch the spring by the initial 15 cm?

A) 230 N
B) 450 N
C) 710 N
D) 360 N
E) 1400 N