To add or remove options in a drop-down menu...

1. Click on the drop-down menu; a grey field settings box will appear:
   
2. To remove an option, click the "x" to the right of that option.
3. To add an option, type it into the white box and click Add; to add multiple options at once, type the options into the white box and separate them with semicolons (no space after the semicolon) and click Add. To remove an option, click the "x" next to that option.
4. If the list of options isn't already sorted alphabetically/numerically, you may want to check the option at the bottom of the field settings box that says "Sort choices."
   
5. Click Save