The only issue I have with A, is that you don’t know it’s a pull back rather than a correction until afterwards. Ex post if you must.
to my mind, It’s only confirmation bias if you buy and it resumes upward progress, if it falls after buying,we are struggling with conservatism as we didn’t appreciate new information.
Good question and one of those that even if you are told the right answer, you can perhaps see round it, a little like most o the ethics questions at Level 3!