Explanation:
For example, when a drum is struck, the flexible skin (sometimes called a membrane) of the drum vibrates. The compression and expansion of the air on either side of the vibrating membrane produces differences in air pressure. The pressure differences generate a sound wave that propagates outward from the drum surface.
Option A, current (thumb) to magnetic field (fingers)
As per the First right-hand rule,
Using right hand, if we suppose that thumb points towards the electric current
fingers curl towards the magnetic field