Please select the best matching pair for each term.

a) Manmade; >50,000 in commercial production; examples include dioxin.
b) Dangerous type of organic chemical; routes of exposure include inhalation and dermal absorption; can occur in any tap water source regardless of source water or location.
c) Controversial water additive; toxic to aquatic life; used for water disinfection.
d) Synthetic organic chemicals (SOCs); Fluorides; Volatile organic compounds (VOCs).