If "AQUARIUMS" is coded as "CCKOSTUWW", then what is the code for "BARBIEQUE"?

Question

The following question was asked in an online assessment by Goldman Sachs, for Engineering undergrads.

If "AQUARIUMS" is coded as "CCKOSTUWW", then what is the code for "BARBIEQUE"?

1. DCTDKGSWG
2. CDGKSTWDG
3. CDDGGKSTW
4. DCGKSTWDG

I tried solving it in the following way:

1. First, I spilt up the word Aquariums from the middle in 2 halves.
2. Next, I found out that each letter in coded word is replaced by it's second sucessor (accoording to English alphabets).

     A Q U A | R | I U M S    [initial codeword]
     C C K O | S | T U W W 
     ^ ^ ^ ^   ^   ^ ^ ^ ^
     A A I M | Q | R S U U    [codeword after rearrangement]  

However, using this logic, I couldn't deduce any meaningful soultion that would match the given options.

Answer 1

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 $3$.

Answer 2

Hint: I'd code AQUARIUM as AAIMQRUU and then compare it with CCKOSTUWW as it has a similar form using lexicographic order.