The correct answer is: c) 1970s.
The Hill State Movement was a political movement in the Indian state of Assam that sought to create a separate state for the tribal peoples of the region. The movement began in the early 1950s, but it was not until the 1970s that it gained significant momentum. In 1972, the Government of India announced its decision to create a separate state for the tribal peoples of Assam, and Meghalaya was officially formed on 21 January 1972.
The Hill State Movement was a complex and multifaceted movement, with a variety of different groups and individuals involved. However, the movement was ultimately successful in achieving its goal of creating a separate state for the tribal peoples of Assam.
The following are brief descriptions of each option:
a) The 1950s: The Hill State Movement did not begin until the early 1960s.
b) The 1960s: The Hill State Movement began in the early 1960s, but it did not gain significant momentum until the 1970s.
c) The 1970s: The Hill State Movement gained significant momentum in the 1970s, and it was during this decade that the Government of India announced its decision to create a separate state for the tribal peoples of Assam.
d) The 1980s: Meghalaya was officially formed on 21 January 1972, so the Hill State Movement could not have culminated in the early 1980s.