Which of the following should be avoided when dealing with a sudden illness?

Letting the person drink fluids should be avoided during a sudden illness for several important reasons. When someone is experiencing a medical emergency, such as a heart attack, stroke, or severe allergic reaction, their symptoms may indicate that their body is not functioning normally. In such situations, the person's swallowing reflex may be compromised, or their condition may require surgical intervention, making it unsafe to ingest any fluids.

Additionally, certain medical conditions can lead to complications if the individual consumes anything by mouth, including choking or aspiration pneumonia. It's generally safer to keep the person calm and wait for emergency medical personnel to arrive rather than risking further complications by allowing them to drink fluids when their medical state is uncertain. Meanwhile, positioning the individual, regulating temperature, and providing reassurance are all appropriate responses to help stabilize the situation until professional help arrives.