Which of the following statements is true about chlorine forms used by utility operators?

Chlorine is a versatile disinfectant used in various forms by utility operators to treat water supplies, ensuring they are safe for consumption. The statement identifying that three forms are commonly used—pure chlorine gas, bleach solutions (sodium hypochlorite), and granular/tablet compounds (calcium hypochlorite)—is accurate.

Pure chlorine gas is often used in large water treatment facilities because of its effectiveness and efficiency in reaching high concentrations needed for disinfection. Sodium hypochlorite, a liquid bleach solution, is used extensively in smaller systems and for disinfection due to its ease of handling and dosage adjustments. Granular or tablet forms make it convenient for dosing in situations where liquid transport may be impractical or when a controlled release is necessary. This flexibility allows operators to choose the best form based on specific circumstances and facility capacities.

Other options incorrectly limit the discussion to either liquids or solids exclusively, or suggest that only gas form is utilized, which does not reflect the common practices and innovations in water treatment.