I arrived upon A as well but without much of the hassle or even putting in numbers
Should've prolly double checked!!!
Acc to the problem statement we have to find r if 27 = nk + r.
Now the first statement gives you 20 = nk + 7, so by substituting nk = 13 in the first statement we can solve for r. (since both should be true for all k). Therefore, SUFF.
In the second statement we get 27 = 2n + r, which is really a specific solution for the problem statement itself - like psdahiya says, no new information. INSUFF.