In this case, <em>heresy </em>is A. expressing beliefs that do not conform to the church.
Explanation:
In a broad sense, <u>heresy</u> refers to any belief or theory that is strongly against what is popularly, officially or customarily established. Particularly in the case of people in the fifteenth century, <u>heresy</u> refers to the beliefs that contradicted a church or religious organization. Therefore, sentence A is the correct answer.