You are a cashier at the cash counter of a hospital. There is no one waiting at the window to pay. You…

The correct choice is: Remain seated at your counter and be attentive to anybody requiring help.

The most professional response is ‘Remain seated at your counter and be attentive to anybody requiring help.’.

A cashier is responsible for the cash counter; it must never be left unattended, and anyone who comes should be served promptly.

Leaving the counter (even to help a co-worker) risks the cash and keeps customers waiting, and listening to music with earphones is unprofessional.