Question

This is a claim: To create a more engaging learning environment, teachers should use a system that randomly determines which students to call on in class.

what is the evidence for this:
answer
1) A study outlined in the Journal of Management Education found that, in classes where teachers randomly call upon students to answer questions, students are more likely to volunteer to speak up in class.
2) Many of my friends say that they often have interesting ideas in class discussions, but they're too shy to share their thoughts with their classmates and teachers.
3) According to one Edutopia article, teachers can improve the quality of classroom discussion by giving students time to think before answering a question.

Answer 1

I'm pretty sure it's the 1st one.

Most definitely not the third one, and unlikely to be the 2nd one. So go for the 1st one.