Which setup would best show how energy spreads from a source?

The best setup to show how energy spreads from a source is B. Candle, Thermometer, Thermometer.

Explanation: In this setup, the candle acts as the energy source (producing heat), and the two thermometers can be placed at different distances from the candle to measure the temperature changes. This demonstrates how heat energy spreads from the source and affects the surrounding environment.