Advanced Search on Multiple Custom Field Values

As an example, I have a single custom field "SelectOne" with 4 selections possible "A","B","C","D".  In my advanced search I want to pull back all tickets with an C or D in SelectOne custom field.  The only criteria option of "is" so must be an exact match to a single value. It appears the Advanced search lets you add another criteria line but seems to be an AND qualifier and not an OR so if I add a 2nd line both options exclude themselves.   So not sure how to do this search to pull back both the C and D tickets. 

I want to do this inside WebHD so it pulls back the actual list of tickets for someone to update.