In Pakistan there is general deficiency of rainfall. It varies from 125 mm annually in upper Sindh to about 900 mm in the sub-mountainous of northern Pakistan. In Balochistan the mean annual rainfall is about 200 mm, diminishing to ________ mm in the desert of Kharan:

In Pakistan there is general deficiency of rainfall. It varies from 125 mm annually in upper Sindh to about 900 mm in the sub-mountainous of northern Pakistan. In Balochistan the mean annual rainfall is about 200 mm, diminishing to ________ mm in the desert of Kharan:

A. 100 mm
B. >70 mm
C. <50 mm
D. None of these