Which of the following is contrary to 'All poets are dreamers'?

The contrary of All poets are dreamers is No poets are dreamers.

Contraries are two universal propositions of opposite quality, the universal affirmative and the universal negative.

They cannot both be true together, yet both may be false.

Moving from all are to none are keeps the universal quantity while reversing the quality.

This universal negative of the same terms is the contrary of the given universal affirmative.