一些史学家常称唐朝为“李朝”、宋朝为“赵宋”，那么被称为“元魏”的是

A．战国时期的魏国

B．北魏

C．三国时期的魏国

D．元朝

Believe it or not, the number of indifferent (漠不关心的) passers-by ______ eighteen, and a large number of people ______ discussing the incident on the net.[ ]

A. add up to; is  

B. add to; is

C. adds up to; are

D. adds to; are