If in an election to a State Legislative Assembly the candidate who is declared elected loses his deposit, it means that

To understand why D is the correct answer, it is important to know the rule regarding the security deposit in Indian elections. According to the Representation of the People Act, a candidate must secure at least one-sixth (16.66 percent) of the total valid votes polled to save their security deposit. In a scenario where the winning candidate loses their deposit, it implies they received less than 16.66 percent of the total votes. This situation can only occur if there is a very large number of candidates contesting the election, causing the total vote share to be fragmented among many people. In such cases, the winner might lead the pack with a very small percentage of the total votes, while the remaining votes are split across numerous other contestants. Options A, B, and C are incorrect because poor voter turnout, multi-member constituencies (which no longer exist in India), or a marginal victory do not automatically result in the winner failing to secure the required 16.66 percent of the total valid votes.