C. consent to reason
Explanation:
In this passage the 'monster' created by Frankenstein comes up to him to reason with him and understands that because he has the ability to reason he cannot be termed a monster. He is only termed a monster because of his hideous physical appearance which cannot betray his character.
This passage is able to convey that the creature has an ability to reason and that he can consent to reason with another over something he disagrees on them with.