(B) National Securities Depository Limited (NSDL)
NSDL and CDSL are the two depositories in India that provide dematerialization of securities.
Source: Chapter 6
The passage clearly states there are two depositories — NSDL and CDSL. RBI is the central bank, NSE is a stock exchange, and SEBI is the regulator; none of them provide dematerialization. Examiners expect the correct option with a one-line justification.