So Multiples of 5 are,
5, 10, 15 and so on.
5 and 10 are the only multiples of 5 in 1-12.
So 2 is the favorable outcome and 12 is the number of possible outcomes.
2/12 would be your proportion
2/12 would be simplified to 1/6
So your answer would be...
B) 1/6!
Hope this helped ;p