Fifty-one percent of U.S. adults oppose hydraulic fracturing (fracking) as a means of increasing the production of natural gas and oil in the United States. You randomly select eight U.S. adults. Find the probability that the number of U.S. adults who oppose fracking as a means of increasing the production of natural gas and oil in the United States is 

(a) Exactly four, 

(b) Less than five, and 

(c) At least three.

Find the indicated probabilities using the geometric distribution, the Poisson distribution, or the binomial distribution. Then determine whether the events are unusual. If convenient, use a table or technology to find the probabilities.