AIDS is said __________ the biggest health challenge to both men and women in that area over the past few years.

A．that it is

B．to be

C．that it has been

D．to have been

某商品房交易估价；评估人员采用市场比较法估价，收集了四个近期交易成交的案例资料，如表4-1：

若对各案例测算出的比准价格结果按加权平均结果处理，且案例B的权重定为0.4。其他两个比准价格的权重均定为0.3时，则按市场比较法求得的评估对象估价结果为( )。

A．2914元/m²

B．2952元/m²

C．2849元/m²

D．2861元/m²