Writing comparative essay on two novels - should I choose one theme or three themes?

I'm in high school and I have to write a comparative essay on two novels. The instruction sheet is very vague (this is pretty much all the instructions given):

"Compare both novels you read on the following: theme. Your essay must be five paragraphs long (introduction, three body paragraphs and a concluding paragraph)."

I'm not sure how to go about writing this essay. I have no idea if my teacher wants me to find one common theme so it's something like this:

Theme: Love

Point 1 (first paragraph): Both protagonists deal with multiple lovers.
Point 2 (second paragraph): Both protagonists fall head over heels in love and they become oblivious to everything else around them.
Point 3 (third paragraph): [one other similarity]

...or should I be choosing three common themes that are evident in both books and do something like this?

First paragraph: The theme of love is demonstrated in both novels by their respective protagonists'....
Second paragraph: The theme of survival is portrayed through their...
Third paragraph: Both novels contain characters whose appearance is different from their reality...

Long story short: when writing a comparative essay comparing theme, should it be based on one theme only or three individual themes?

I think you should choose one theme so you can focus and go in depth