Impossible
Neither likely nor unlikely
Certain
1) Let's analyze each situation.
Edna has a bag of chocolates. There are 12 milk chocolates, 14 dark chocolates, and 9 chocolate-covered almonds. She reaches into the bag without looking and picks one chocolate-covered cherry.
We can tell that the likelihood, in this case, is impossible for there is no such candy in the bag (chocolate-covered cherry).
2) Note that we've got here in the word M I S S I S S I P P I 11 letters. Since there are 4 letters S and 2 letters p, the probability of picking a card with p or s is neither likely nor unlikely,
3) In the case of Dorothy, we've got here a certain likelihood, since this is an all-girls school. And therefore, there are no boys in there.