The correct answer is A) preventing infection. The primary concern in treating a person with extensive burns is to prevent infection, as this is the leading cause of death in burn victims. Preventing infection is crucial because the burned skin is no longer able to act as a barrier against bacteria and other pathogens, leaving the patient vulnerable to life-threatening infections. Proper wound care, including cleansing and dressing the burns, is essential to minimize the risk of infection. While other factors like reducing swelling and disfigurement are also important, preventing infection is the most critical concern in the initial treatment of extensive burns.