Which theorem is the most popular?

And the winner is: Very clearly:
The divergence theorem!
Give it up for the divergence theorem. The second rank was Pythagoras theorem. In general, there was a very strong correlation between the choice of the number and the final score in the course. Faster students liked the integral theorems, slower students the theorems which appeared earlier. But it was not universal. Some students with high scores chose Pythagoras or Al Khashi too.

The reason for the competition was a little project of mine over the summer.