The kindhearted man,who thinks ________his duty to help poor people,is popular with many people who know him.
A:it
B:that
C:one
D:this
“周人以西方的一个小国代商而有天下,苦于兵力单薄,不足以镇压东方各族人民,于是大封同姓、异姓及古帝王之后于东方,以为周室的‘藩屏’”。对以上材料理解正确的是( )