A 10-year-old boy is brought to the emergency room because of a headache. For the past three days, he has had a fever and a headache. Then, this morning his mother noted the presence of a rash. He denies vomiting, abdominal pain, neck pain, or coughing. Last week, he went hiking with his father although he denies any tick bite. On physical examination, temperature is 38.7℃, heart rate is 88 per minute, and respiratory rate is 23 per minute. There is a blanching erythematous rash with macules on the ankles and wrists. Which of the following is the most likely diagnosis?a. Leptospirosisb. Meningococcal meningitisc. Rocky Mountain spotted feverd. Thrombotic thrombocytopenic purport