The Securities and Exchange Board of India (SEBI) is the regulatory authority for the securities market in India. Its primary functions include regulating the securities market, protecting the interests of investors, and promoting the development of the securities market.
Among the options provided, the registration of brokers and sub-brokers is a direct regulatory function of SEBI, as it ensures that only qualified and compliant entities operate in the market. The other options, while relevant to the functioning of the securities market, do not fall under the regulatory functions of SEBI.