Which of the following are ways to improve database performance? Select all the options that apply.

A) Compact the database regularly.
B) Add more memory.
C) Convert the database to an earlier format.
D) Close other open applications you do not need.

A) Compacting a database can help improve performance by reducing file size and thus making data retrieval more efficient. B) Adding more memory (RAM) to a system can significantly improve database performance, especially for operations that require large data sets to be loaded into memory. D) Closing other open applications can free up system resources such as CPU and memory, which can then be utilized more effectively by the database, thereby improving its performance. C) is incorrect because converting a database to an earlier format does not inherently improve performance and can, in fact, lead to compatibility and functionality issues.