Typically, a survey question will ask for someone to select one option or select many. Also, the system would like to clear any choices, if Don’t know is selected.
- Cannot change the question
- Unlikely to be able to change the system behavior, but I will recommend allowing users to decide what to do or revert if selected and something was selected/entered.
Prevent any confusion or errors when all other selections are lost after selecting Don’t know. Letting them know what just happened, and helping them recover.
Your gut reaction O1 or O2?
What do you think of O1 and O2? What if the word grouping label repeats the question? The goal here is to show that Don't know is different or to allude to the system behavior.