A private bus company gained greater profits and provided bus service

IMO D. Using the negating technique of Power score gmat critical bible

A private bus company gained greater profits and provided bus service to the area at lower fares by running buses more frequently and stimulating greater ridership. Hoping to continue these financial trends, the company plans to replace all older buses with new, larger buses, including some double-decker buses.

The plan of the bus company as described above assumes all of the following EXCEPT
(A) the demand for bus service in the company’s area of service will increase in the future --> if not, the company will not gain expected profit
(B) increased efficiency and revenues will compensate for any new expenses the company incurs --> if not, the company must stand a negative business outcome
(C) the new buses will be sufficiently reliable to ensure the company a net financial gain once they are in place --> if not, the company can't be sure about its future positive outcome
(D) driving the new buses will be no more difficult than driving the buses they are to replace --> if not, it is still too far to conclude that the company can't have expected profit. So, it's the best
(E) the larger, double-decker buses will not face obstacles such as height and weight restrictions in the bus company’s area of service --> if not, the company can't run its plan as initially thought and, thereby can't achieve expected profit