Final answer:
A linear model would predict a decrease in gasoline on the jet after 18 hours of flight because it represents a constant rate of fuel consumption over time.
Step-by-step explanation:
We can predict the amount of gasoline on the jet after 18 hours of nonstop flight using a linear model to represent gasoline consumption over time. Assuming that the rate of consumption is constant, the linear model would show that as time increases, the gasoline amount would decrease due to constant usage.
Therefore, the linear model predicts a decrease in gasoline after 18 hours, which aligns with choice (c).