Answer: A

The knowledge point to be assessed in analyzing this question is contractual investment funds. Contractual funds are a type of fund established based on a fund contract. In our country, contractual funds are established based on the fund contract signed between the fund manager and the fund custodian. Fund investors become fund share holders and parties to the fund contract after obtaining fund shares, and enjoy rights and assume obligations in accordance with the law. . Contractual funds rely on the management and operation of fund managers for investment. Therefore, in the operational relationship of contractual funds, the fund manager is at the core. Therefore, the answer to this question is A.