All athletes who come first, second or third in their event are tested for banned substances. Once samples are taken, they are each tested twice using Test X and Test Y. If the athlete used a banned substances, Test X has a 90% probability of being positive, while Test Y has an 80% chance of being positive. Each test is independent of each other. What is the probability that at least one test is positive if the athlete has used a banned substance? Select one: a. 0.82 O b. 0.80 c. 0.90 O d. 0.98 e. 0.72