Question

Why should Vishal take notes in preparation for a group discussion?

to show that he researched the topic
to have access to supporting information
to ensure that the facts remain objective
to remind him of new topics to introduce

Answer 1

to have access to supporting information

Notes give Vishal quick reference to facts, examples, and sources he can cite during the discussion. (They may also help remind him of topics to introduce, but the primary purpose is to support his points.)