All the statements are accurate. Illiquid assets do generate an illiquidity premium, which can make the fund attractive to investors seeking higher returns. However, a high proportion of illiquid assets can be a warning signal for investors as it may indicate potential liquidity risk. This is because illiquid assets can be difficult to sell quickly without incurring a significant loss in value. The valuation of such assets is often not transparent, which can further increase the risk. Therefore, the model used for the valuation of these assets should be independently audited to ensure its accuracy and reliability. Furthermore, the use of proprietary models that are not independently audited can make the valuation process more opaque and increase the risk of fraud. Therefore, this is also a warning signal for investors.

Choice A is incorrect. While it's true that illiquid assets can generate an illiquidity premium, making the fund attractive, this isn't the only accurate statement among the options. Other statements also hold true in certain contexts.

Choice B is incorrect. Although both statements I and II are correct, they do not represent all the accurate statements in this context. Statements III and IV are also correct as per FRM guidelines which emphasize on independent auditing of models used for valuation of illiquid assets and consider use of unaudited proprietary models as a warning signal.

Choice C is incorrect. While it's true that both statements III and IV are accurate, they don't encompass all the correct answers here. Statements I and II are also valid under certain circumstances.