<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 7-year-old boy is brought to the physician because of a 5-day history of fever, malaise, and joint pain. He had a sore throat 4 weeks ago that resolved without treatment. His temperature is 38.6C 101.5F and blood pressure is 8462 mm Hg. Physical examination shows several firm, painless nodules under the skin near his elbows and the dorsal aspect of both wrists. Cardiopulmonary examination shows bilateral basilar crackles and a blowing, holosystolic murmur heard best at the cardiac apex. Both knee joints are warm. Laboratory studies show an erythrocyte sedimentation rate of 129 mmh. The immune response seen in this patient is most likely due to the presence of which of the following?? A: Hyaluronic acid capsule, B: TSST-1, C: IgA protease, D: CAMP factor, E: M proteinn,  <response>: This is a clinical vignette describing a 7-year-old boy with fever, malaise, joint pain, and skin nodules after a recent sore throat. The key findings are the skin nodules, heart murmur, elevated erythrocyte sedimentation rate ESR, and history of sore throat. This presentation is most consistent with acute rheumatic fever, which can occur after a streptococcal pharyngitis infection. The immune response in rheumatic fever is due to antibodies formed against streptococcal M proteins cross-reacting with tissues in the heart, joints, skin, and brain. Therefore, the answer is most likely E, M protein.E: M protein 