The regulatory body for Mutual Funds is the Securities Exchange Board of India (SEBI). All mutual funds must get registered with SEBI.
Source: Chapter 7, "What is the Regulatory Body for Mutual Funds?"
This is a direct one-line fact question. Just naming SEBI earns the mark, but expanding it slightly to "SEBI, and all mutual funds must register with it" shows completeness. Always write the full form — examiners expect it for 1-mark definitional answers.