Which is the best example of a monarch supporting enlightenment reform

The best example of a monarch supporting enlightenment reform is Joseph II abolishing serfdom in Austria.

Explanation:

Joseph II ruled over the most substantial kingdom of Central Europe during 1780 and reflected as the best instance of a monarch who supported enlightenment reform. The formation of civil liberties for the serfs in fundamental levels replaced the Habsburg lands' traditional serfdom culture.

This act was resulted when Joseph II sanctioned the "Serfdom Patent" in 1781. But final abolishment of serfdom in the Empire was marked in 1848 only. He also formulated reformation of education and public health during his rule which was inspired from Joseph II's mother.