Two towns are connected by railway. Can you find the distance between them? I. The speed of the mail train is 12 km/hr more than that of an express train. II. A mail train takes 40 minutes less than an express train to cover the distance.

1. A Option A: I alone sufficient while II alone not sufficient to answer
2. B Option B: II alone sufficient while I alone not sufficient to answer
3. C Option C: Either I or II alone sufficient to answer
4. D Option D: Both I and II are not sufficient to answer
5. E Option E: Both I and II are necessary to answer

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