In South Asia, sparsely populated areas are primarily found in:
A. Coastal areas - Generally, coastal areas in South Asia are not sparsely populated as they tend to attract people for agriculture, fishing, and trade.
B. Areas with an arid climate - Yes, areas with an arid climate, such as parts of western Rajasthan in India and the Thar Desert, tend to be sparsely populated due to limited water resources and harsh living conditions.
C. Areas with heavy rainfall - No, areas with heavy rainfall, such as parts of the Western Ghats and northeastern India, are often densely populated due to fertile land and favorable conditions for agriculture.
D. Areas in the humid temperate climate region - Generally, these regions are not present in South Asia but are more common in temperate zones found further north or in different geographical contexts. The humid subtropical areas of South Asia, such as parts of northern India, can be populous, so they do not fit as sparsely populated areas.
In summary, the correct answer regarding sparsely populated areas in South Asia is B. Areas with an arid climate.