男，16岁。颈部肿大1年，无怕热、多食、易激动。查体：脉率、血压正常，甲状腺弥漫性肿大，质地柔软，未触及结节，表面光滑。采用的最佳治疗措施是（）

A.多吃含碘丰富的食物

B.小剂量甲状腺素治疗

C.口服甲基硫氧嘧啶治疗

D.注射I¹³¹治疗

E.甲状腺大部切除术

An analyst does research about various companies and stocks. A company has experienced stable earnings over the previous years and the company has a high beta. These factors best describe a:

A. cyclical company and a defensive stock.
B. defensive company and a cyclical stock.
C. defensive company and a defensive stock.