I think there is no single rule to choose which one might the best option.
If you are dealing with market entry case, then you could talk about for the following:
All of those will be valid areas to look into since you might want to analyze how each can affect your potential goal.
In a more specific case where the client already entered into business and there is a profitability issue, you might want to breakdown as Internal/External or still use a combination of the factors I mentioned above.
The goal is to be flexible on any case and not force fit any pre-designed framework but be quick and flexible enough to create one on the spot. That's how it sounds authentic. Also there are many cases where you can't simply use any of the frameworks above (exception Profitability) like:
-Why are the number of giraffes decrease in Australia?
-Why did the elevator wait time increased in client's office last year?