OCP - Performance Tuning

I've just been sent the following question from an OCP test, and I can't decide whether this is a subtle trap, or a naive interpretation of the manuals on the part of the examiner.

I haven't been told whether this is a 'single answer only' question, or 'perm any N'. But I assume from the grammar that precisely one answer is supposed to be correct.

If you were taking the exam, which one would you put ?

(NB - I didn't say "which one is correct?").

4. The cost-based optimizer can choose between a nested

    loops join and a sort merge join operation. All tables are     analyzed and the OPTIMIZER_MODE is set to FIRST_ROWS.     Which execution plan will be the result?

1. The sort-merge join.
2. The nested loops join.
3. This depends on some sort parameter values.
4. This depends on the number of rows in each table.

--
Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

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