The correct options are
A Sikkim became part of India in 1975.
C Sikkim was ruled by Chogyals before it was included into the Indian Union.
D Sikkim shares its boundary with Nepal, Bhutan and Tibet.
Sikkim became part of India in 1975. It was ruled by Chogyals before it was included into the Indian Union. It shares its boundary with Nepal, Bhutan and Tibet. Eleven languages are spoken in Sikkim.