Hi Craig,
Thanks for posting on our forum.
Based on my test, I would like to explain that it is not feasible to create the drop down list on Microsoft Forms.
Given the situation, we welcome and encourage you to share your ideas through User Voice. It is the best way to perfect our products and services. Many features have been developed or upgraded directly from your ideas:
create an option to allow for people in your organization to be a drop down list answer.
If you have created the drop down list on Microsoft Forms, could you please provide the detailed steps?
Thanks for your understanding.
Qing