$7.$ Consider a simple pendulum consisting of a small ball on a string, undergoing SHM$.$ Which of the statements below is correct for the moment when the pendulum passes through the equilibrium position: $($a$)$ the linear velocity is zero $($b$)$ the angular velocity is zero $($c$)$ the total linear acceleration is zero $($d$)$ the total linear acceleration is not zero $($e$)$ the angular acceleration is not zero