Run into a problem with this one.. I am interpreting cheating as an ongoing state rather than something that is happening at this instant and, from the choices available, thought "être trichants" to better reflect that than "en train de".. this was in a general test and not specifically testing "en train de"
What would be the best way to say... "He realizes you're cheating."?
Il réalise que vous êtes en train de tricher.
Il réalise que vous êtes trichants.