Investors of contractual funds become parties to fund contracts by purchasing fund shares, and enjoy corresponding rights and obligations. Option a is wrong. Closed-end funds have a fixed fund share, which is suitable for investors whose funds can be invested for a long time. Option b is wrong. Classifying funds according to investment objects (stock funds, bond funds, money market funds and mixed funds) helps investors to establish a preliminary understanding of fund risks and returns, and option C is wrong. Passive fund is a fund manager who chooses a specific index component as the investment object in order to be able to keep pace with the replicated index performance. Option d is wrong.