38. 腦下腺機能亢進(hyperpituitarism)最常見的原因為： (A)腦下腺腺瘤(pituitary adenoma) (B)腦下腺增生(pituitary hyperplasia) (C)腦下腺腺癌(pituitary carcinoma) (D)下視丘疾病(hypothalamic disease)