If "AQUARIUMS" is coded as "CCKOSTUWW", then what is the code for "BARBIEQUE"?
Hint: I'd code AQUARIUM as AAIMQRUU and then compare it with CCKOSTUWW as it has a similar form using lexicographic order.
Sort the letters alphabetically:
$$BARBIEQUE\to ABBEEIQRU$$
Now replace each letter with the letter two places forward ($A\to C, B\to D\ldots$):
$$ABBEEIQRU\to CDDGGKSTW$$
so the right answer is $3$.