A particle of mass $0.3 kg$ is subjected to a force $F=-kx$ with $k=15 N/m$. What will be its initial acceleration if it is released from a point $20 cm$ away from orgin?

Question

$$(a)\;3\;m/s^2 \quad (b)\;15\; m/s^2\quad (c)\;5\;m/s^2 \quad (d)\;-10\;m/s^2$$