It boils down to this: whether you are retaliated by the company for reporting A. To figure that out, you should ask for a copy of your personal record and get a copy of the company's employee manual, particularly the section regarding employee discipline. Your past performance, reviews, warnings, etc. can be greatly helpful in evaluating whether you have a case.
There may be other grounds, such as age, sex, discrimination, disability, etc, but you will need proof and witness.
Companies can fire one for insubordination but not likely without a warning first. There are missing facts to say one way or the other.