ANSWER:
a. Award a touch for X.
If no penalties have been given. While retreating, Fencer X parries Fencer Y’s attack and ripostes, touching Y on the valid surface, which is registered on the machine. X retreats then fall; Y’s remise arrives on the valid surface, which is registered on the machine the referee should a ward a touch for X.
Explanation:
a. Award a touch for X.
If no penalties have been given. While retreating, Fencer X parries Fencer Y’s attack and ripostes, touching Y on the valid surface, which is registered on the machine. X retreats then fall; Y’s remise arrives on the valid surface, which is registered on the machine the referee should a ward a touch for X.