Bose is (1)/ more popular than (2)/ any student in the class. (3)/ No Error (4)

Here, any other student in the class .... should be used.

Look at the sentences :

No other singer in the school is as good as

Hari. — Positive degree

Hari is the best singer in the school. — Suplerlative degree

Hari is better than any other singer in the

school.— Comparative degree