Identify the FOUR foam proportioning methods used in firefighting.

The correct answer highlights the four primary foam proportioning methods utilized in firefighting: induction, injection, batch mixing, and pre-mixing. Induction refers to the process where foam concentrate is drawn into the water stream using a venturi effect or similar mechanism, allowing for the mixing of foam and water at the nozzle or pump. Injection involves the direct addition of foam concentrate into the water stream from a source, ensuring an accurate proportion of foam to water as it's delivered.

Batch mixing is a method where a specified amount of foam concentrate is mixed with water in a separate tank before being used, ensuring consistent concentration for firefighting efforts. Pre-mixing involves preparing the foam solution in advance, saving time during an emergency as the firefighting crew can deploy the ready foam solution immediately.

Other choices include methods that either do not represent standard practices in foam proportioning or combine terms and concepts related to foam use that are not typically classified as proportioning methods. Understanding these four methods is crucial in effective firefighting, ensuring that firefighters can use foam efficiently and safely to combat fires, especially in scenarios involving flammable liquids.