17. You are playing the one-armed bandit (slot machine) . There are three wheels, and on each wheel there is a picture of a lemon, a plum, an apple, an orange, a pear, cherries, and a banana (seven different pictures). You insert your silver dollar and pull down the lever. What is the probability that a. Three oranges will appear? b. Two oranges and a banana will appear, without regard to order? c. At least two oranges will appear?