The correct answer is 'ten minutes to twelve'.

Solution:

• The time is 11:50 means the minute hand is pointing at 10.
• The time is 11:50 means the hour hand is between 11 and 12,
• It takes ten minutes for the minute hand to move from 10 to 12.

Since, the minute hand only needs ten minutes to move from 10 to 12, and the hour hand is between 11 and 12.

Then, the time 11:50 is 'ten minutes to twelve'.