Siyaram Tewari belongs to which of the following music Gharanas?

The correct answer is Darbhanga.

Pandit Siyaram Tiwari (1919–1998) was a distinguished Indian classical singer and one of the leading exponents of the Dhrupad genre. He belonged to the renowned Darbhanga Gharana of Bihar.
For his extraordinary contributions to Hindustani classical music, he was honored with the prestigious Padma Shri award in 1971 and the Sangeet Natak Akademi Award in 1984.

About the Darbhanga Gharana:
1. It is one of the principal tradition-rich schools of Dhrupad singing in India.
2. The Darbhanga style of Dhrupad is particularly noted for its expressive balance between the structured improvisational Alap and dynamic Layakari (rhythmic playfulness).