Creating a 'If-need-be' poll allows your participants to indicate the options that they could make if need be. To enable this feature, tick the box "if need be" during step 3 of the poll creation.
When your participants make their selections in your poll they can choose 'if-need-be' by clicking the option twice. When 'if-need-be' is enabled the box will turn orange.
Try it now: Create a yes-no-ifneedbe poll