<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 22-year-old man comes to the physician for a follow-up evaluation for chronic lower back pain. He has back stiffness that lasts all morning and slowly improves throughout the day. He has tried multiple over-the-counter medications, including ibuprofen, without any improvement in his symptoms. Physical examination shows tenderness over the iliac crest bilaterally and limited range of motion of the lumbar spine with forward flexion. The results of HLA-B27 testing are positive. An x-ray of the lumbar spine shows fusion of the lumbar vertebrae and sacroiliac joints. The physician plans to prescribe a new medication but first orders a tuberculin skin test to assess for the risk of latent tuberculosis reactivation. Inhibition of which of the following is the most likely primary mechanism of action of this drug?? A: Inosine monophosphate dehydrogenase, B: TNF-α, C: NF-κB, D: Calcineurin, E: mTOR kinase,  <response>: This is a clinical vignette describing a patient with chronic lower back pain and findings consistent with ankylosing spondylitis. The physician plans to start a new medication for this condition but first wants to check for latent TB with a tuberculin skin test, as the medication can increase the risk of TB reactivation. Based on the information provided, the physician likely plans to start a TNF-alpha inhibitor, as these are commonly used to treat ankylosing spondylitis. The question asks about the primary mechanism of action of this planned medication. TNF-alpha inhibitors work by blocking the inflammatory cytokine TNF-alpha. Therefore, the correct answer should be an option that inhibits TNF-alpha.B: TNF-α 