3.d analysis: N' low altitude, high pressure, A wrong; M' the terrain is higher than N', and the temperature is lower, and B is wrong; Affected by monsoon climate, there is much precipitation, and C is wrong.

C analysis: n' is located in the Three Gorges area of the Yangtze River and is rich in hydropower resources, but the area with the richest hydropower resources in China is the southwest, so d does not meet.