The column not returned by 'OPTIMIZE TABLE' is . . . . . . . .

This question is asking about what information is NOT shown when you use the OPTIMIZE TABLE command in MySQL.
OPTIMIZE TABLE is a command used to improve the performance of your table by reorganizing the data and making it easier for MySQL to access.
The OPTIMIZE TABLE command usually shows information like:
- Table: The name of the table being optimized.
- Op: The operation being performed (e.g., 'optimize').
- Msg_type: The type of message (e.g., 'status').
- Msg_txt: A message describing the results of the optimization.
So, the answer is Option B: Msg_txt.
The Msg_txt column contains a detailed message about the optimization process, but it's not the output you'd usually see from the OPTIMIZE TABLE command.