You are answering a USMLE-style medical question. Question: A 27-year-old male presents to the psychiatrist requesting help with his compulsions as they are interfering with his life. He explains that he has this fear that something terrible will happen to his house if he does not check every appliance, outlet, window and door lock, faucet, and light fixture before he leaves. He states that he must check everything 7 times in a specific order and if he goes out of order he must start from the beginning and perform it all over. He has recently been fired from his job because he is always late and lost his fiancee as she could not deal with his habits anymore. The physician explained that cognitive-behavioral therapy may be of assistance and also prescribed clomipramine. Which of the following is the mechanism of reaction of clomipramine? Options: A) Decreases the degradation of norepinephrine and serotonin B) Increases the release of norepinephrine and serotonin by alpha 2 receptor antagonism C) Blocks only norepinephrine reuptake D) Blocks reuptake of norepinephrine and serotonin Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.