<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 3-year-old boy presents to the office with his mother. She states that her son seems weak and unwilling to walk. He only learned how to walk recently after a very notable delay. The boy was born at 39 weeks gestation via spontaneous vaginal delivery. He is up to date on all vaccines and is meeting all verbal and social milestones but he has a great deal of trouble with gross and fine motor skills. Past medical history is noncontributory. He takes a multivitamin every day. The mother states that some boys on her side of the family have had similar symptoms and worries that her son might have the same condition. Today, the boys vital signs include: blood pressure 11065 mm Hg, heart rate 90min, respiratory rate 22min, and temperature 37.0C 98.6F. On physical exam, the boy appears well developed and pleasant. He sits and listens and follows direction. His heart has a regular rate and rhythm and his lungs are clear to auscultation bilaterally. He struggles to get up to a standing position after sitting on the floor. A genetic study is performed that reveals a significant deletion in the gene that codes for dystrophin. Which of the following is the most likely diagnosis?? A: Duchenne muscular dystrophy, B: Becker muscular dystrophy, C: Limb-girdle muscular dystrophy, D: Myotonic muscular dystrophy, E: Emery-Dreifuss muscular dystrophy,  <response>: Based on the information provided in the question stem, the 3-year-old boy has delayed motor development, especially with walking, as well as weakness and difficulty with gross and fine motor skills. His family history is notable for similar symptoms in males on his mothers side. Genetic testing revealed a deletion in the dystrophin gene. Duchenne muscular dystrophy is an X-linked recessive disorder caused by mutations in the dystrophin gene. It typically presents in early childhood with delayed motor milestones and proximal muscle weakness. The description and genetic test results are most consistent with Duchenne muscular dystrophy.Becker muscular dystrophy is less likely as it has a later onset and slower progression. Limb-girdle and myotonic muscular dystrophies also do not match the presentation. Emery-Dreifuss affects a different gene and has early contractures.A: Duchenne muscular dystrophy 