An airline has two daily one-way flights operating from Istanbul to Vienna. Each flight takes the same path, and hence covers the same distance \(D\) every time. The 1st flight travels at a speed between 600 mph and 800 mph and covers \(D\) in 2.5 hours. The 2nd flight travels at a speed between 800 and 1000 mph and covers \(D\) in 1.75 hours. Which of the following could be the possible value(s) of \(D?\)

I. 1500
II. 1620
III. 1750

A. Only I
B. Only II
C. Only III
D. Only I and III
E. All of the above

Answer: B

Source: e-GMAT