This is no laughing matter. We may well lose our jobs over this ___________.
(A) accident (B) incident
The answer to the above question is A. Is option B also acceptable?
I need native speakers' help.
Yes, and I would even venture to say that it would be more common. I would put it this way: Every accident is an incident, but not every incident is an accident. People shouldn't lose jobs over an accident unless it was caused by some negligence.
It has been my experience that a lot of teachers in Asia do not have the depth of training or experience to truly understand English enough to accept alternative answers to questions. They know only that one answer is 'correct' which to them must mean that all other answers must be 'incorrect'. The question was poorly written.