A customer’s small heterogeneous enterprise has grown over time to more than 500 client systems， and the administrator cannot add new servers to the management database.  Which of the following is the most likely source of the problem？（）

• A、The management server has reached its size limitation.
• B、Additional agent licenses must be purchased.
• C、The CPU and Memory requirements need to be upgraded.
• D、The default JET database has reached its size limitation.