What is the most logical next event?

Young boys are shown doing a karate demo in front of the judges. they

OPT:
a). practice quickly how to execute a martial art using their hands in steps while with their heads lowered.;
b). use a black belt and a nunchaku.;
c). practice with swords and perform several different moves.;
d). move back and forth and front to back performing various punches.;
d).