Currently with the "checkmatrix" type, users can check how many options as they want. There should be an option to limit the number of checkboxes to tick to one.
From John on Miraheze Phab (https://phabricator.miraheze.org/T4477#85085):
A matrix of radio buttons is an extremely common survey feature and is desirable in the situation we’ve used them in place.
Turning one question into 7 separate questions creating a longer and less user friendly design is less desirable. If the radio options were across and not down, it would be acceptable to split them but still not ideal.
@Aklapper is that a suitable use case?