How can I limit the number of selections of a choice in a drop down menu

Just to clarify, you want to put a limit on how many times the user can pick the options in the dropdown field? If yes, that's possible but in a checkbox field using this widget https://widgets.jotform.com/widget/gift_registry. Just define the options as well as the number limit. The number of selected options will be deducted per submissions.

If you need further assistance, let us know.