<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:An otherwise healthy 10-day-old boy is brought to the physician by his parents because of progressively enlarging breasts bilaterally for the last 4 days. The parents report that they have sometimes noticed a discharge of small quantities of a white liquid from the left breast since yesterday. During pregnancy, the mother was diagnosed with hypothyroidism and was treated with L-thyroxine. The patients maternal grandmother died of breast cancer. The patient currently weighs 3100-g 6.8-lb and is 51 cm 20 in in length. Vital signs are within normal limits. Examination shows symmetrically enlarged, nontender breasts, with bilaterally inverted nipples. The remainder of the examination shows no abnormalities. Which of the following is the most appropriate next step in the management of this patient?? A: Reassurance, B: Breast biopsy, C: Serum gonadotropin measurement, D: Chromosomal analysis, E: Mammography,  <response>: This is a case of a 10-day-old infant boy with bilateral breast enlargement and discharge from one breast. The differential diagnosis includes physiological transient breast enlargement, precocious puberty, and tumors. The history of maternal hypothyroidism raises suspicion for transient hypothyroidism in the infant, leading to temporary breast enlargement. This is the most likely diagnosis given the patients age and lack of other abnormalities on exam. Breast biopsy and mammography would be inappropriate next steps due to the patients young age. Measuring serum gonadotropins and chromosomal analysis may be indicated if the breast changes persist, but are premature at this stage.A: Reassurance 