What was the primary concern of the Assam Movement from 1979 to 1985?

The correct answer is Option 4 - Detection and deportation of illegal Bengali Muslim settlers

Explanation: The primary concern of the Assam Movement from 1979 to 1985 was the detection and deportation of illegal Bengali Muslim settlers from Bangladesh. The movement aimed to address the fear that these settlers would reduce the indigenous Assamese population into a minority. While economic issues and concerns about the exploitation of natural resources were also raised during the movement, the central issue was the perceived threat posed by the presence of illegal immigrants from Bangladesh. This movement took a political and sometimes violent form as the Assamese people sought to protect their demographic and cultural identity.