A hiker attempting to cross a wilderness area has two GPS systems of intermittent reliability because of the areas remoteness .from past experience he estimates that at any moment the probability that system I will work is 0.85, that system II will work is 0.90 , and both will work is 0.80 . the probability that at any moment at least one of the systems will work is about. A. 0.87
B. 0.92
C. 0.75
D. 0.95
E. 0.88