The Correct answer is C.

Explanation

The outcome space for this experiment is the set of all ordered pairs??where?represents the first number that comes up, and??represents the second one. Since??and??can take all the values??through?, there will be a total of??possible outcomes. The outcomes can be represented in a table as shown:

Among all the pairs?,??are pairs for which?. So??remaining pairs will have?. Notice that the number of pairs???for which??is the same with the number of pairs?

?for which?. Therefore the number of pairs?

?for which?, is?(half of?). Then the probability that??is equal to?.