Disapointing and Lame trick question.
The question asked which row had the "largest defined row size", not "the largest storage size".
The answer in the the reference material is for a differant question.
Storage size and defined size are two differant concepts.
The following quote is from the books online section on how to choose between ROW and PAGE compression.
Compression can allow more rows to be stored on a page, but does not change the maximum row size of a table or index.
So even though the maximum storage size of the data is less with compression on, the defined maximum row size of the data is not any differant.