The infrastructure of a country is makes everything run smoothly， including things like transport， irrigation， electricity， postal service， telephones and schools.
A. that
B. what
C. which
D. as
网友回答
A. that
(答案→)B. what
C. which
D. as
解析：考查名词性从句。句中what引导表语从句，在从句中作主语，故选B。