What happens next?

The biker is cycling and jumping over the big ramps. The biker jumps in the ramp with his bike in front up. four bikers

Available choices:
a). on different parts of the track bikes cross at the same time.;
b). stand by the ramp talking and pointing.;
c). with their bikes entering into a ramp are inside a factory.;
d). raced and jumped over the ramps, the biker in white is leading in the race.;
d).