Interesting question.

There is however a problem with use of imprecise English - this is of course sheer nit-picking, and I'm not complaining because I guessed that the chances were better than even that imprecise English was being used so that I got it "right" by deliberately selecting an answer I knew to be wrong.

The right answer of course is "each of them can (but only one at a time)" so of the options provided 3 is closest to correct. 1 (the "right" answer) would only be really correct if the question was "how many of them can be rowguidcol columns at the same time".