Answer:
A. His conscience gets the better of him, and he does not want to be Edward Hyde any longer.
Step-by-step explanation:
This is the main reason why Hyde decides to drink the potion and transform back into Jekyll. Hyde was a terrible being, but his great advantage was the fact that he was free to do whatever he wanted with impunity. While this is attractive at first, eventually his conscience gets the better of him. Feeling guilty about the ways in which he had behaved, he decides he does not want to be Hyde any longer.