getting data from sheets is easy if you're willing to make it public, even some tutorials on the platform: https://next.observablehq.com/@bryangingechen/importing-data-from-google-spreadsheets-into-a-notebook-we doing it via some authenticated way looks like Google makes it kinda harder and harder https://github.com/jsoma/tabletop (see warnings) maybe best is to encourage uploading a file attachment? CSV is pretty universal and that way there is no confusing access controls and API keys etc

this is very much like the counting we do in a regular single choice answer. the difference is in the percentage, if you add all these counts up you'll get more than the # of survey respondents (since a single person can count towards multiple answers)