That's a terrible test question!
It can't be (1) because the article is wrong. You would have to use "an" with "effective". Saying an "effective effect" is rather clunky writing, but not inherently wrong.
But the other 3 are all possible.
I'd say (2) is the best choice, because it is both grammatically valid and makes the most logical sense.
A "focusing effect" makes sense. The accident caused her to become more focused in her thinking.
A "total effect" doesn't make sense in this context. Total of what? You could say, "The total effect of the accident was that it made her more cautious" or some such. But to say it had a "total effect", what does that mean?
A "wide effect" is possible but awkward. It could mean that if affected many things. But a fluent speaker would be more likely to say, "a broad effect".
So I'd say (2) is the best choice and (4) is possible. (1) is wrong and (3) is unlikely.
How anyone could say that (3) is correct and (2) and (4) are wrong is just ... baffling.