Final answer:
The best treatment for diaper dermatitis is to apply petroleum jelly to the affected area; this provides a protective barrier against moisture and irritants.
Step-by-step explanation:
To treat diaper dermatitis, the most effective option is A) Applying petroleum jelly to the affected area. This approach helps by creating a barrier to protect the skin from moisture and irritants. It is important to avoid B) Using bleach directly on the diaper, as this could be harmful to the baby's skin.
Additionally, C) Using scented baby wipes for cleaning is not recommended because fragrances can further irritate sensitive skin. Finally, D) Applying spicy ointments to reduce irritation is incorrect and should be avoided as they can cause more irritation to the already sensitive skin.