Answer:
Roman engineers used inverted siphons to move water across a valley if they judged it impractical to build a raised aqueduct. The Roman legions were largely responsible for building the aqueducts. Maintenance was often done by slaves. The Romans were among the first civilizations to harness the power of water.
Explanation:
In the 1920's and 1930's gained popular support was by appealing national pride. So it’s C hope it helps :D