Final answer:
A backdraft is the result of introducing fresh air into a confined, hot, fuel-rich, and oxygen-starved environment, causing an explosion due to sudden combustion.
Step-by-step explanation:
Introducing fresh air into a hot, fuel-rich, oxygen-starved environment can result in B) Backdraft. A backdraft is a phenomenon that occurs when oxygen is introduced into a confined space where a fire has consumed most of the available oxygen, leading to a situation that is rich in combustible gases but lacks the oxygen needed for these gases to burn. When fresh air enters the space, it mixes with the combustible gases and comes into contact with the still-hot surfaces or embers, which can ignite the gases, causing an explosion.
Combustion is a rapid chemical reaction that combines molecules of oxygen with molecules of fuel, resulting in the release of energy. In the case of a backdraft, the combustion process has been interrupted due to a lack of oxygen, but the introduction of fresh air suddenly supplies the necessary oxygen, resulting in a rapid combustion in the form of an explosion. This process is an example of an exothermic redox reaction.