Choice A rationale:

Taking aspirin is not recommended for individuals with chickenpox, especially children, as it has been associated with an increased risk of Reye syndrome, a severe and potentially fatal condition affecting the brain and liver.

Choice B rationale:

Applying topical antibiotics is not a suitable recommendation for relieving pruritus (itching) associated with chickenpox. Topical antibiotics are used to treat bacterial skin infections, not pruritus.

Choice C rationale:

Using antihistamines is the most appropriate recommendation for relieving pruritus in chickenpox. Antihistamines block the effects of histamine, a chemical released during an allergic reaction or infection, and can help reduce itching.

Choice D rationale:

Increasing physical activity is not advised for a client with chickenpox, as this could lead to the spread of the virus to others and may worsen the symptoms and pruritus.