The dropdown type question only allows selecting a single option from a list of options. The field code can be used in URL parameters, and a single value can be passed as shown below.
https://example.neetocal.com/sample-meeting?dropdown=Not sure
If the passed value is not a valid option for the dropdown question, no value will be selected. See the example below.
https://example.neetocal.com/sample-meeting?dropdown=invalid