Speculation and gambling are two different actions used to increase wealth under conditions of risk or uncertainty. Gambling refers to wagering money in an event that has an uncertain outcome in hopes of winning more money, whereas speculation involves taking a calculated risk in an uncertain outcome.
It's actually U.S. and England.
The question isn't very clear, but it is referencing the transatlantic cable which goes from England to North U.S.
A, happened during the war so I dont know if that counts since it has nothing to do with the treaty of Versailles. B, is what actually made it impossible for the Weimar Republic to succeed. For C, I mean it didnt do that, as far as I know so I would go with D.