I feel like it is A but you would need a second opinion on that one
It was that "Flat land with poor drainage led to salinization from irrigation waters," that was a factor in the decline of Sumer, since this led to a build up of salt in the soil, which greatly reduced agricultural output.
Because he found out to make great cool discoveries the the invenstion of the bomb, but other scientists turned his discovery into a atomic bomb, which he thought was wrong. Thye soon blast the bomb on a country and he tried really hard to stop them but they didnt listen, soon countries developed their own bombs and shooted at the other countries threatiing them/
They led revolutions in favor of affecting the spanish regime/they didnt like it