<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 is brought to his pediatrician by his parents for a follow-up visit. Several concerning traits were observed at his last physical, 6 months ago. He had developmental delay, a delay in meeting gross and fine motor control benchmarks, and repetitive behaviors. At birth, he was noted to have flat feet, poor muscle tone, an elongated face with large, prominent ears, and enlarged testicles. He takes a chewable multivitamin every morning. There is one other member of the family, on the mothers side, with a similar condition. Today, his blood pressure is 11065 mm Hg, heart rate is 90min, respiratory rate is 22min, and temperature of 37.0C 98.6F. On physical exam, the boy repetitively rocks back and forth and has difficulty following commands. His heart has a mid-systolic click, followed by a late systolic murmur and his lungs are clear to auscultation bilaterally. Several vials of whole blood are collected for analysis. Which of the following studies should be conducted as part of the diagnostic screening protocol?? A: Northern blot with DNA probes, B: Southern blot with DNA probes, C: Two-dimensional gel electrophoresis, D: PCR followed by northern blot with DNA probes, E: Western blot,  <response>: This is a clinical vignette describing a 3-year-old boy with developmental delay, motor delays, repetitive behaviors, dysmorphic facial features, and enlarged testicles. He also has a heart murmur. The stem asks which diagnostic study should be done as part of the screening protocol. Based on the clinical features described, this patient likely has a genetic or chromosomal disorder. The choices describe different molecular biology techniques that could be used to diagnose a genetic condition. A Southern blot uses DNA probes to look for abnormal DNA sequences. This would be an appropriate screening test to identify deletions, duplications, or other abnormalities in the childs DNA.B: Southern blot with DNA probes 