6. The Environmental Protection Agency regulates the amount of lead in tap water. (3pt) According to EPA regulations, if lead concentrations exceed 15 ppb in more than 10% of customer faucets sampled then the local Water Department must take "additional steps" such as replacing service lines and informing the public. Note: ppb means "parts per billion". Suppose that in a particular city a large number of faucets were tested and lead levels recorded and the 85th percentile was determined to be 16 ppb. Assume that the sample is large enough for the EPA to obtain meaningful results. Must the water department in this city take "additional steps"? Choose the single answer that best describes your conclusion and reasoning. a. Yes; additional steps are required because 85% of the faucets tested have a lead level equal to 16 ppb. b. Yes; additional steps are required because at least 15% of the faucets tested have lead levels higher than 15 ppb. c. Yes; additional steps are required because at least 85% of the faucets tested have lead levels higher than 15 ppb. d. Not enough information is provided to answer this