What is the most logical next event?

This video allows viewers to hear the testimony of a customer who has used the pro roofing service. first the man

a). tells how he heard about the service and how great it is.;
b). poured wet cement on the gutters of a building and the roof of a building he works in followed by removing shingles from the roof.;
c). takes out a sample piece of paper and cuts a piece out.;
d). coats the roofing with a coating of cement.;
a).