You are answering a USMLE-style medical question. Question: A 3-year-old refugee with increasing pitting edema and abdominal swelling over the past 2 months is brought to the physician. Her family has been displaced several times over the last few years. Nutrition and housing were frequently inadequate. At the physician’s clinic, the boy appears irritated and drowsy. He is difficult to arouse. Physical examination shows pitting edema over the ankles and feet and around his eyes. Abdominal examination is positive for ascites and hepatomegaly. Oral examination shows several missing teeth. Which of the following best explains these findings? Options: A) Kwashiorkor B) Marasmus C) Beriberi D) Rickets Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.