I just verified that the correct answer given is indeed A A A (Option 4) (and not A B A). There haven't been any updates to this question either so it has been like that for quite a while.
A detailed explanation is also provided with this option:
There are two things here:
1. When you don't specify the argument index or relative indexing (i.e. the < flag) in the format specifier, it means that you are using ordinary indexing. Each format specifier that uses ordinary indexing is assigned a sequential implicit index into argument list which is independent of the indices used by explicit or relative indexing.
The ordinary index starts with the first format specifier that does not use explicit index.
In this case, it starts with the middle %s. Therefore, it prints the first argument which is A.
2. < is used for relative indexing. It means you want to use the argument that was used for the previous format specifier. In this case, it was A. Therefore, it prints A again.
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For ocpjp7, the difficult level of this mock exam is very similar to that of real oracle exam, according to other ranchers feedback.
That's why I postpone the exam date because my score on the mock exams are not very good. But, from the experience other ranchers shared on the result board, their mock exam scores were also not very good.
And for the string format topic, there are some tiny corner questions like this in real oracle exam.