单项选择题
A.绝对高程B.海拔C.高差D.相对高程
A.1m,2m,5mB.0.001m,0.002m,0.005mC.0.01m,0.02m,0.05mD.0.1m,0.2m,0.5m
A.等高距越大B.地面坡度越陡C.等高距越小D.地面坡度越缓