Most wild freshwater fish carry parasites which usually don't affect the health of the fish. Due to environmental changes, parasites can increase and result in fungal and tapeworm infections causing visible symptoms on fish.

In fish observed at one location, 15% had fungal infections, 7% had fungal and tapeworm infections and 9% were infected with tapeworm. Let A be the event that a fish has a fungal infection, and let B be the event that a tapeworm infection is present. Using a Venn diagram or otherwise, answer the following:

a) What is the probability that a fish doesn't show any signs of a fungal or tapeworm infection?

b) Calculate P(A or B).

c) Find P(B|A).

d) Are fungal and tapeworm infections independent events? Explain.