<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 19-year-old woman presents to the dermatology clinic for a follow-up of worsening acne. She has previously tried topical tretinoin as well as topical and oral antibiotics with no improvement. She recently moved to the area for college and says the acne has caused significant emotional distress when it comes to making new friends. She has no significant past medical or surgical history. Family and social history are also noncontributory. The patients blood pressure is 11877 mm Hg, the pulse is 76min, the respiratory rate is 17min, and the temperature is 36.6C 97.9F. Physical examination reveals erythematous skin lesions including both open and closed comedones with inflammatory lesions overlying her face, neck, and upper back. The patient asks about oral isotretinoin. Which of the following is the most important step in counseling this patient prior to prescribing oral isotretinoin?? A: Avoid direct sunlight, from 10am to 2pm, B: Wear a wide-brimmed hat outdoors, C: Use non-comedogenic sunscreen daily with SPF of at least 45, D: Document 2 negative urine or blood pregnancy tests before beginning oral isotretinoin, E: Apply topical retinoids in the evening before bed,  <response>: This is a patient with moderate to severe acne that has not responded to previous topical and oral antibiotic treatments. The question asks about the most important step when considering oral isotretinoin, which is a very effective treatment for severe recalcitrant nodular acne. However, it is absolutely contraindicated in pregnancy due to risk of severe birth defects. Therefore, the most important step before starting oral isotretinoin is to ensure the patient is not pregnant by documenting two negative pregnancy tests. Choices A, B, C, and E are good general skin care recommendations but not the most critical step for this patient being considered for isotretinoin.D: Document 2 negative urine or blood pregnancy tests before beginning oral isotretinoin 