Forecast drivers,in air carrier revenue forecasting,are many and varied.Which one of the statements below is correct?

A.Revenue passenger miles (RPMs) is not a useful tool.

B.Crude oil prices are an excellent and useful indicator at predicting future jet fuel prices.

C.Industry passenger revenue as a percent of GDP;use of leading economic indicators is a good qualitative measure.

D.Load factor (LF)trends rarely provide good information.