单选题 M点高程HM=43.251m,测得后视读数a=1.000m,前视读b=2.283m。则视线高Hi和待求点N的高程HN,分别为( )。
A.45.534m;43.251m B.40.968m;38.685m
C.44.251m;41.968m D.42.251m;39.968m

【正确答案】 C
【答案解析】[解析] Hi=HM+a=1.000+43.251=44.251m;HN=Hi-6=44.251 -2.283=41.968m.