In the Middle Ages, who would have been considered a heretic by the church?

Options:
A European knight who did not join the crusades
A Christian who did not follow accepted church teachings
A Muslim who fought against Christian crusaders in Jerusalem
A Jew who refused to convert to Christianity

All the given options would have been considered heretics by the church during the Middle Ages.

Pick one correct answer

A Jew who refused to convert to Christianity would have been considered a heretic by the church during the Middle Ages.