Which intervention is appropriate in promoting the infant's comfort and preventing complications?

The correct answer is A: Elevating the legs on a pillow. Elevating the legs helps improve circulation, reduce swelling, and promote comfort in infants with casts. This intervention prevents complications such as pressure ulcers and circulation problems. Applying heat therapy (B) can actually increase swelling and discomfort. Removing casts for bathing (C) can compromise the integrity of the cast and lead to complications. Encouraging crawling and weight-bearing (D) can worsen the condition and delay healing.