Problem: A 16-year-old boy is brought to your office by his parents on a Monday morning because he noted his urine appeared red in color. He is known to you. He has a history of participating in numerous high-risk behaviors in the previous year, including binge drinking and ingestion of various drugs as well as accepting eating challenges. He discloses to you that he had some recent upper respiratory infection symptoms and that he had been partying with his friends over the weekend. His physical examination does not reveal any specific abnormalities. His blood pressure is 125/65 mm Hg. A urinalysis (UA) shows reddish urine. The urine dipstick is 3þ positive for blood but negative for protein. The spun sediment performed by the laboratory shows only some granular casts but no red blood cells (RBCs). Which of the following diagnoses most explains these findings in this patient? A. Acute postinfectious nephritis. B. Acute liver injury. C. Acute muscle injury. D. Immunoglobulin A nephritis. E. Paprika ingestion.