Supplementary speech materials could be:

a. facts

b. examples

c. stories

d. all of the above

D. All of the above

When structuring a speech you want to make sure you have a balance of different types of information. You want to provide the audience with facts so that it's clear you've done your research and have a solid grasp of the technical aspects of the topic. You also though, want to incorporate personal stories and examples to draw the audience in and make them emotionally invested in your topic and the people it affects.