In Act 4 of "The Crucible," Abigail pretending to feel a cold wind is primarily a tactic to manipulate the situation. The best answer to your question is:
B. She's accusing Mary of witchcraft to protect herself.
Abigail is trying to divert attention away from herself and her actions. By pretending to be affected by a cold wind, she aims to create a scene that reinforces the idea of supernatural occurrences, thereby shifting blame and potentially saving herself from the consequences of her own actions.