If the user should make a choice between different values DCR graphs supports the data type "Choice".
Historically we have presented choices as a drop down list, but with DCR Portal 6.9 and forward the user can choose to present choices as a radio button field, either horizontal or vertical.
This example graph shows the difference.
If you open the graph in the Activty Editor and view it as a form you will see the different options:
Note: Remember to set the width of a vertical field to Large to ensure that all text can be viewed.
Notice the new Radio drop down list which can have the values None (default), Horizontal or Vertical.