Which one of the following statements is correct?

Explanation:

The correct statement is B.

A) The largest Buddhist monastery in India is in Assam. This statement is incorrect. The largest Buddhist monastery in India is Tawang Monastery, which is located in Arunachal Pradesh, not Assam.

B) The language Konyak is spoken in Nagaland. This statement is correct. Konyak is one of the major indigenous languages spoken by the Konyak Naga tribe, primarily in the Mon district of Nagaland.

C) The largest river island in the world is in Assam. This statement is incorrect. While Majuli in Assam is often cited as the largest purely riverine island, Marajó Island in Brazil, located at the mouth of the Amazon River, is significantly larger and is generally considered the largest river island in the world, even though it has some fluvio-maritime characteristics.

D) Sikkim is the least populated state of the Indian Union. This statement is factually correct as per Census 2011 data; Sikkim has the lowest population among all Indian states. However, in UPSC questions, sometimes a single best answer is expected, and other options might be considered "less correct" due to subtle interpretations or common misconceptions. If the question implies the entire Indian Union (including Union Territories), Lakshadweep is the least populated overall. But since it specifies "state," Sikkim is indeed correct. Given that B is the correct answer, there might be an implicit reason for D to be considered incorrect in the context of the question setter, possibly to distinguish it from a broader "least populated entity in India" which would include UTs. However, based purely on the phrasing "least populated state," it is correct. For the purpose of this analysis, and assuming only one option is correct, the ambiguity or potential for broader interpretation of D makes B a more unequivocally correct statement.