means "nothing through the mouth" and is the withholding of fluids and food by mouth.

NPO (nil per os) means "nothing through the mouth" and is the withholding of fluids and food by mouth.

Explanation:

Nil per os is a medical instruction not to feed the patient food or drink. It literally means "nothing through the mouth", and it implies that the patient cannot ingest any type of food or drink for a certain period of time. Generally, patients are indicated NPO when they are going to receive a total anesthesia in case of surgeries, since when they come into contact with substances present in food, anesthesia can generate allergic reactions that can potentially be fatal for the patient.

i say that the answer is 'd'