You can decide whether a Multiple Choice Question in a survey is
Unlimited multiple choice: i.e. the respondent can select as many Answers as they like to that question
Limited multiple choice: i.e. the respondent can select up to a specific number of Answers, based on a limit you define
Single multiple choice: i.e. the respondent can only select one Answer to that question (This is the default option)
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Go to the Create/Edit Survey Template page
Click the blue number in the Multiple Choice Type box
You arrive in the Multiple Choice Type popup
The setting will be set to whichever Type has already been chosen (the default is Single)
Limited Multiple Choice allows you to limit the number of answers that can be chosen
Unlimited Multiple Choice allows someone to select all the answers if they so choose
Press submit in the popup
The popup closes and the symbol in the Multiple Choice Type box for that question will have updated
Press save Save