Recently our class held a fierce _____ as to whether cameras should be installed in public areas.

A．conflict

B．debate

C．bargain

D．contest

有关维生素B12所致的巨幼红细胞性贫血的描述，错误的是

A．精神神经症状突出

B．血清维生素B12含量低于100ng/L

C．维生素B12治疗有效

D．重度贫血者可予输血治疗

E．应先加用叶酸联合治疗