Correct Answer: Both assertion and reason are true, and the reason is the correct explanation of the assertion.

Solution : The correct answer is (a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.

The assertion states that SEBI's development functions focus on regulating credit rating agencies. This is true because SEBI (Securities and Exchange Board of India) is indeed involved in regulating and overseeing credit rating agencies to ensure they operate in a transparent and accountable manner.

The reason given is that SEBI aims to promote the orderly growth and development of the securities market. This is also true, as one of SEBI's primary objectives is to promote the development and regulation of the securities market in India, ensuring it functions efficiently and in a manner that benefits investors and the market as a whole. Regulating credit rating agencies is a part of this broader objective to ensure a well-functioning securities market.