1.) From your form's Dashboard, select 'Edit Form Contents' from underneath the 'Quick Links' selection near the top of the page.

2.) Select the section of the form that you want to add a drop-down question to.  

3.) Here you can edit what the section looks like.  To add a new question to the section, select 'Add Question' in the list of tool options under 'Form Contents'.

4.) Fill out the fields required for the question.  In order to make the question have a drop-down selection, select 'Drop Down' from the drop-down menu under 'Type'.

NOTE: 'Field Name' will be automatically filled in when you enter the 'Question Text'.

5.) Selecting this option will change the format to fill out the question's answers.  For a drop-down question, you must designate each option you want to be an answer by entering values into the boxes provided.  The choice values will automatically be filled in.  Click the green '+' button to add the value to the list of answers.

6.) After you have entered all the question values that you wish to be included, add the question to your form by clicking 'Save Changes' at the bottom of the window.