What happens to the respiratory centre during swallowing?

a) Signals from the swallowing centre in the brainstem inhibit the respiratory centre.

Explanation:
Swallowing is a complex reflex coordinated by the swallowing center in the brainstem. During the pharyngeal phase of swallowing, this center sends inhibitory signals to the respiratory center, also located in the brainstem. This temporary inhibition of breathing, known as deglutition apnea, ensures that the airway (trachea) is closed off by the epiglottis and vocal cords, preventing food or liquid from entering the lungs.

The final answer is $a$