Answer:
C) 0.72
Explanation:
Let A represent the event that a client chooses to visit Italy on a tour. Let B represent the event that the client chooses to visit Greece. As a client may visit both countries on the same tour, the events A and B are not mutually exclusive.
P(A or B) = P(A) = P(B) - P(A and B) = 0.55 + 0.28 - 0.11 = 0.72
So the probability that a client chooses Greece, or Italy, or both countries, on a tour is 0.72.