Hola Mó

The reason why it's marked as wrong is because what we are testing in that test-question is the verb "volver", not the verb "regresar" as it says on the hint: "Conjugate "volver" in El Presente"

It's necessary to follow what it is instructed in the hints, otherwise the testing and scoring wouldn't make sense. 

I hope this clarified it.

Saludos

Hola Carlos

Yes, two verbs that mean the same: volver and regresar

: ))