Answer: A

Funds with different operating modes have different trading places and methods, and the liquidity of fund products is different. For example, closed-end funds are mainly traded through exchanges; Open-end funds are mainly purchased and redeemed at the fund's direct sales and consignment outlets; Individual open-end fund varieties, such as ETF, can be listed and traded on the exchange, and can also be purchased and redeemed by portfolio securities in the primary market. In addition, the operating characteristics of funds with different operating modes will also be different. For example, in the operation of open-end funds, some cash should be reserved to cope with redemption, while the liquidity requirements of closed-end fund portfolio operation will be lower, and the risk-return characteristics of the two types of funds will inevitably be different.