You can do it!
Motivate your answer? Who talks like this?! How exactly does one go about motivating an answer? This is just as ridiculous as “Defend your answer” from earlier! It’s like teachers are actively trying to get their students to fill in the weirdest answers possible.
Although answers are emotionless, we feel that offering emotional support to an answer might be the right thing to do. This is especially true if the student pulled an answer out of thin air without any basis of knowledge or fact. In that case, go, answer, go! We believe in you, even if the teacher doesn’t!