<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 56-year-old man comes to the physician because of lower back pain for the past 2 weeks. The pain is stabbing and shooting in quality and radiates down the backs of his legs. It began when he was lifting a bag of cement at work. The pain has been getting worse, and he has started to notice occasional numbness and clumsiness while walking. He has hypertension and peripheral artery disease. Medications include hydrochlorothiazide and aspirin. His temperature is 37C 98.6F, pulse is 82min, and blood pressure is 13392 mm Hg. Peripheral pulses are palpable in all four extremities. Neurological examination shows 55 strength in the upper extremities and 35 strength in bilateral foot dorsiflexion. Sensation to light touch is diminished bilaterally over the lateral thigh area and the inner side of lower legs. Passive raising of either the right or left leg causes pain radiating down the ipsilateral leg. Which of the following is the most appropriate next step in management?? A: X-ray of the lumbar spine, B: Erythrocyte sedimentation rate, C: MRI of the lumbar spine, D: Therapeutic exercise regimen, E: PSA measurement,  <response>: This is a patient with lower back pain radiating to the legs along with numbness, clumsiness while walking, and weakness in foot dorsiflexion. The description of the pain and the neurological findings are concerning for a lumbar radiculopathy likely due to a herniated intervertebral disc compressing a nerve root. Imaging of the lumbar spine is needed to evaluate for this. An X-ray would not provide adequate visualization of the intervertebral discs and nerve roots. Erythrocyte sedimentation rate is a non-specific inflammatory marker and would not be useful. Therapeutic exercise could be considered after making the diagnosis but is premature at this point. PSA is unrelated to the presenting symptoms. Therefore, MRI of the lumbar spine is the most appropriate next step to visualize the discs, nerve roots, and surrounding structures.C: MRI of the lumbar spine 