Using a bitmap structure to manage database object space has several benefits over using freelist structures. Which three are benefits of managing space using automatic-segment-space managed objects？（）

• A、It readily responds to dynamic changes for concurrent access. 
• B、It improves performance and space utilization in a multiple-instance environment. 
• C、It requires fewer space related options then freelist managed structures. 
• D、It improves performance for SYSTEM tablespaces where a high degree of concurrency is required.