You are answering a USMLE-style medical question. Question: A researcher hypothesizes that low birth weight is related to obesity later in life. He conducts a study with a 95% confidence interval with a p-value of 0.049 to disprove his null hypothesis. He rejects his null hypothesis and concludes that low birth weight is associated with obesity. Which of the following statements best associates with his study? Options: A) Confidence interval should have been 90%. B) A type 2 error is not possible in this case. C) A type 2 error has been made. D) A type 1 error has been made. Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.