How i came to this answer was adding all of the number of medals together for all of the years, coming up to a total of 22. When asking about probability of any given set or amount of things, you always take the selected values and take them out of the whole amount. Years 2009 and 2012 have a whole selected value of 11 (4+7). Therefore you're "taking" 11 from 22, coming up with the fraction 11/22 seeing as that is not a answer choice the next step is to simply the fraction to 1/2.
