The relationship proof pictures are UP TO 20 pictures. Most people would like to submit more than 20. You are the first who ask to have the option of NOT to provide any picture for relationship proof.
As question 7 is country specific, I have no idea of your answer A - D becauce you didn't state what is the PA's country.
In general, include pictures to show how your relationship developed and pictures at wedding and other pictures with families and friends is the general idea.