The correct answer is: a) Chogyal.
The Chogyal was the hereditary ruler of Sikkim from the 17th century until 1975. The title was abolished in 1975 after Sikkim became a state of India. The abolition of the Chogyal’s title was part of a larger effort to promote social equality in Sikkim.
The other options are incorrect because they are not titles that were abolished in Sikkim. Kazi is a title given to a high-ranking official in Sikkim. Lopen is a title given to a Buddhist monk. Gyalpo is a Tibetan title for a king or ruler.
The abolition of the Chogyal’s title was a significant event in Sikkim’s history. It marked the end of the hereditary monarchy and the beginning of a new era of democracy and social equality.