The correct answer is A. Chamba.
The SCs male literacy rate in Chamba is 69.8%, which is the lowest among all the districts of Himachal Pradesh. The SCs male literacy rate in Una is 72.3%, the SCs male literacy rate in Sirmaur is 73.2%, and the SCs male literacy rate in Kangra is 74.1%.
The SCs male literacy rate is the percentage of males from the Scheduled Castes who are literate. The Scheduled Castes are a group of people who have been historically discriminated against in India. The SCs male literacy rate is an important indicator of the social and economic status of the Scheduled Castes.
The SCs male literacy rate in Chamba is low because of a number of factors, including poverty, lack of access to education, and social discrimination. The government of Himachal Pradesh has taken a number of steps to improve the SCs male literacy rate, including providing scholarships, building schools in remote areas, and running awareness campaigns. However, more needs to be done to improve the SCs male literacy rate in Chamba.