Showing count of zero with pivot table

Hi! 

I am aggregating survey responses and so each question has multiple choice answers "Strongly Agree, Agee, Neutral, Disagree, Strongly Disagree". When creating a pivot table, I want all of these options to appear even if the count of them for a particular question (i.e. pivot table) is zero. 

When I go to PivotTable options > Display, the button "Show items with no data on rows" is greyed out and I cannot select it. Can someone help me?