You are answering a USMLE-style medical question. Question: A 21-year-old female presents to the clinic requesting prenatal counseling. She was born with a disease that has led her to have recurrent upper respiratory infections throughout her life requiring antibiotic prophylaxis and chest physiotherapy as well as pancreatic enzyme replacement therapy. She marries a man (without this disease phenotype) from a population where the prevalence of this disease is 1/100. What is the chance that their child will have the disease of interest? Options: A) 9/100 B) 1/10 C) 81/100 D) 9/10 Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.