The number of people invited ___fifty, but a number of them____ absent fordifferent reasons．

A．were; was

B．was; was

C．was; were

D．were; were.

某公司新建办公楼需要装修，若由甲工程队单独完成需要18周，若由乙工程队单独完成需要12周．现在招标的结果是由甲工程队先做3周后，再由甲、乙两队合作，共需装修费4000元．若按各队完成的工作量付给装修费，该如何分配？