Which of the following is the defining condition for a particle to execute simple harmonic motion (SHM)?
(a) The restoring force is directly proportional to the displacement but directed away from the mean position.
(b) The magnitude of the restoring force is directly proportional to the magnitude of displacement and always directed toward the mean position.
(c) The restoring force is proportional to the square of displacement and directed toward the mean position.
(d) The particle moves with constant speed along its path.