(C) Where accessible deep aquifers are the best choice as a source for a municipal water supply
(D) The regional government’s standards allow some bacteria in municipal water supplies
(E) Chlorine is the least effective disinfecting agent
4.Which one of the following, if true, most helps explain the difference in bacterial contamination in the two groups of municipalities?
(A) Chlorine is considered by some experts to be dangerous to human health, even in the small concentrations used in municipal water supplies.
(B) When municipalities decide not to chlorinate their water supplies, it is usually because their citxens have voiced objections to the taste and smell of chlorine.
(C) The municipalities that did not add chlorine to their water supplies also did not add any of the other available water disinfectants which are more expensive than chlorine.
(D) Other agents commonly added to public water supplies such as fluoride and sodium hydroxide were not used by any of the 50 municipalities