Which of the follong statements about IPO is correct? a. In a firm environment cash offer, the underwriter would buy the whole issue from the issuer, and then sell the issue to the market. b. In a market without agency problems, Dutch auction is the worst among the three IPO methods in terms of finding out the best reservation price of the IPO shares. C. In the best effort cash offer, a firm would have to continue the issuance even of the demand does not meet their expectation. D. Best efforts cash offer is the most popular IPO method in the US market.