When analyzing the complete model, which can predict short-run and long- run changes in the exchange rate, one must: A) start with short-run changes and move toward long-run changes, and thereby determine expectations. B) use only the long-run model because the short-run model is largely irrelevant. C) start with the long-run equilibrium positions where expectations of future exchange rates can be determined and use those expectations to feed into the short-run model. D) use the short-run model only, because the long run is only a theoretical concept