A large part of the Kalahari desert is located in the nation of

A-Malawi

B-Botswana

C-Mozambique

D-Congo-Kinshasa

Botswana is mostly covered by the Kalahari Desert, along with few regions of Namibia. According to the geographical statistics, Botswana's seventy percent territory is covered by the Kalahari desert. That makes the option B. Botswana, the country mainly covered by the Kalahari Desert.