Choice A rationale:

 "Avoid exposing your child to allergens and irritants." This is the most appropriate preventive measure for eczema.

Minimizing exposure to allergens and irritants can help prevent eczema flare-ups in children who are at risk.

This includes avoiding triggers such as certain foods, dust mites, pet dander, and harsh soaps.

Choice B rationale:

 "Encourage frequent hot baths for better skin health." This statement is not accurate.

Hot baths can actually exacerbate eczema symptoms by drying out the skin.

It is recommended to use lukewarm water for bathing and to apply moisturizers immediately after bathing to lock in moisture.

Choice C rationale:

 "Apply scented lotions to keep the skin moisturized." This statement is not accurate.

Scented lotions can contain irritants that may worsen eczema symptoms.

It is advisable to use fragrance-free and hypoallergenic moisturizers for eczema-prone skin.

Choice D rationale:

 "Expose your child to cold, dry air to toughen the skin." This statement is not accurate.

Cold, dry air can actually contribute to skin dryness and worsen eczema symptoms.

It is important to maintain proper skin hydration and protect the skin from harsh environmental conditions.