Final answer:
Time has the greatest effect on lowering Blood Alcohol Concentration (BAC) because it allows the body to metabolize and eliminate alcohol at a constant rate.
Step-by-step explanation:
The question you're asking is about what has the greatest effect on lowering Blood Alcohol Concentration (BAC). Of the options you have provided, time is the most significant factor that affects the lowering of BAC. The liver metabolizes alcohol at a constant rate, and while food can slow the absorption of alcohol and exercise may have a minimal impact on metabolism, it is the passage of time that is required for the body to process and eliminate alcohol from the system.