Users in PROD database reported about the slow responses of the transaction. While investigating the reason you find that the transactions are waiting for the undo segments to be available, and undo retention has been set to zero. What would you do to overcome this problem?

When undo retention is zero and transactions wait for undo segments, it means the undo tablespace is full and cannot create new extents. Increasing the size of the undo tablespace provides more space for undo segments, allowing concurrent transactions to proceed. Creating another undo tablespace doesn't help the current one. Increasing retention without space is ineffective. Creating more segments manually is not the solution.