Choose the correct phrase to complete the dramatic soap opera dialogue.

You can try to stop the wedding, Alejandro, but by the time you arrive at the church, Maria _____ someone else!

The correct answer is will have married.

We use the Future Perfect (will have married) to show that the action of getting married will be already finished before the second future event (Alejandro arriving at the church) happens. "Will marry" would mean she waits for him to arrive and then marries someone else!