Explanation

(c) In case of SHM, when motion is considered from the equilibrium position, velocity at an instant $t$ is given by
$v = \omega\sqrt{A^{2} - y^{2}}$
At the mean or equilibrium position $ie$, when $y = 0$
$v = v_{\max} = \omega A$
At the extreme positions, $ie$, when $y = \pm A$
$v = v_{\min} = 0$
Hence, velocity is maximum at equilibrium position.