Choice A rationale:

Instructing the parents to teach the child to cover their mouth and nose when coughing or sneezing is crucial in preventing the spread of infections, especially in cases of gastroenteritis.

This measure helps in containing respiratory droplets that might carry the virus or bacteria causing the illness.

Choice B rationale:

Isolating the child in a separate room away from other family members is essential to prevent the transmission of the disease to others in the household.

Gastroenteritis spreads through contaminated food, water, or contact with an infected person.

By isolating the child, the risk of spreading the infection to family members is significantly reduced.

Choice C rationale:

Washing hands thoroughly with soap and water after handling the child's soiled items is a fundamental hygiene practice.

Proper handwashing removes bacteria and viruses from the hands, preventing the spread of infections.

Teaching the parents this measure ensures they do not inadvertently transfer the bacteria to surfaces or other people in the household.

Choice D rationale:

Sharing utensils and towels with the child is not an appropriate measure to prevent the spread of gastroenteritis.

This behavior increases the risk of cross-contamination and can lead to other family members becoming infected.

It is important to stress the importance of personal hygiene items to limit the spread of the disease.

Choice E rationale:

Disinfecting surfaces and toys that the child has come into contact with is crucial in preventing the spread of gastroenteritis.

The virus or bacteria causing the illness can survive on surfaces for a certain period, making it essential to regularly disinfect commonly touched items.

This measure reduces the risk of other family members coming into contact with the pathogens and getting sick.