One end of an elastic string of natural length / and modulus X is kept fixed while to the other end is attached a particle of mass m which is hanging freely under gravity. The particle is pulled down vertically through a distance x, held at rest and then released. The motion is___________________?
(A) a simple harmonic motion
(B) a rectilinear motion with constant speed
(C) a damped oscillatory motion
(D) none of the above

