Solution:
Since 2k + 2 is always even, we only need to deal with the even factors of 180. Furthermore, since k is a positive integer, the least value of 2k + 2 is 2(1) + 2 = 4. That is, we are only looking for the even factors of 180 that are greater than or equal to 4.
Since 180 = 1 x 180 = 2 x 90 = 3 x 60 = 4 x 45 = 5 x 36 = 6 x 30 = 9 x 20 = 10 x 18 = 12 x 15, we see that there are 11 such factors (they are in bold).
Answer: C
