Translation:The driver will leave my grandmother at the association after the party.
My answer, "the driver is going to leave my grandmother at the association after the party" was marked incorrect and THIS was correct? "The driver is going to leave my grandmother to the association after the party." No one would leave a grandmother "to" an association (in English).
Only accents make the difference: Avó or vó - grandmother; vovó or even vovozinha - granny, grandma. Avô or vô - grandfather; vovô or vovozinho - grandpa.
P.S. Zoom in (+) if you cannot see the "acento agudo" and the "acento circunflexo". With little characters difference is invisible here.
Your suggested answer that "the driver would leave my grandmother TO the association" is absolute "cobblers" Duo. Unless of course the driver was donating my poor aged grandmother to an association as some sort of research item!! The fact that this blatant error is still online after 5 years is very poor. By the way my answer "The motorist will leave my grandmother at the association was marked incorrect"....which it isnt!!!