Final answer:
The nurse should instruct the parent to use an over-the-counter medication containing permethrin to treat pediculosis capitis in the child.
Step-by-step explanation:
The nurse should include the instruction to use an over-the-counter medication containing 1% permethrin in the teaching for the parent of the child with pediculosis capitis. Permethrin is a common treatment for head lice infestations and is effective in killing the lice and their eggs. The nurse should explain how to properly apply the medication according to the product's instructions.
Applying mayonnaise to the affected area at night is not an evidence-based treatment for head lice and there is no scientific evidence to support its effectiveness. Treating household pets is also not necessary as head lice infestations are specific to humans. Therefore, option B is incorrect. Discarding the child's stuffed animals is not necessary as lice do not survive very long away from the human scalp.