$\begin{array}{1 1} \text{(a)Freon is a colorless gas with a choking or suffocating odor.} \\ \text{(b)Freon is a harmful CFC found in many older air conditioning units} \\ \text{(c)Freon is a useful gas found in many older air conditioning units.} \\ \text{(d) Freon is a highly reactive gas composed of three oxygen atoms.}\end{array} $
