1. The Venn diagrams are used for both classification and comparisons. Don't limit to only one of them.
2. Venn diagrams don't have to be circles.
3. You need to draw the universal set.
4. Venn diagrams don't have to be very simple. It's okay to complicate the Venn diagrams in order to capture the classifications and the comparisons.
He tells them what can he do to figure out his solution to the problem.
"To write a novel", is the subject in the infinitive phrase.
His ultimate goal is to write a novel. So, "To write a novel" functions as a noun in the sentence. Hence, the answer is A. Noun.
