Final answer:
In pediatric patients, a severe burn is classified by depth and extent, with full-thickness burns covering 15% of the body surface area considered severe due to the depth of tissue damage.
Step-by-step explanation:
In considering the severity of burns in a pediatric patient, we must classify them by the depth and extent of skin damage. A fourth-degree burn, where full-thickness of the skin as well as underlying muscle and bone are damaged, is among the most severe. Therefore, option 3, which features full-thickness burns that cover 15% of the body surface area, is considered severe for a pediatric patient.
This classification is more severe due to the depth of tissue involvement compared to superficial and partial-thickness burns, regardless of the percentage of body surface area affected.