Which option lists all basic types of foam systems?

• A. Fixed
• B. Semi-fixed
• C. Portable
• D. All of the Above

Answer: (D)

Foam systems are categorized by how they’re deployed: fixed, semi-fixed, and portable. Each of these represents a basic way foam can be applied in a firefighting setup. Because all three types are considered fundamental options, the choice that lists every category is the best answer. Fixed systems are permanently installed with built-in piping and proportioning equipment; semi-fixed systems combine some fixed elements with portable components; portable systems involve mobile, hand-held or trolley-mounted foam devices for quick, flexible response. In practice, selection depends on the environment, access, and operational needs, so including all three covers the full range of basic options.