某家电企业派专人到商场调查顾客的购买情况，其采用的方法是

A．重点调查

B．典型调查

C．观测法

D．实验法

The subway was crowded with passengers going home from market, most of _____ carrying heavy bags and baskets full of fruit and vegetables they had bought there.

A．whom

B．them

C．who

D．which