What is wrong with "hebben gekozen" here?
I guessed so, but I still lost a heart over writing "De kiezers hebben een nieuwe president voor de republiek gekozen."
The course is still in beta so it's possible that alternative translations are missing. You can help the course builders by reporting these using the "report a problem" button during lessons.
It might have worked with "gekozen" before "voor" (just a guess!)