Which sentence, if added after sentence 2, would give readers the BEST overview of the research and main ideas? a.
It was the biggest thing anyone had ever seen, and Americans were thrilled to have built it.
b.
It was more expensive than any other public project that had ever been built before in the United States, but cost was beside the point where Hoover Dam was concerned.
c.
It was constructed in a surprisingly short period of time under harsh conditions; and it tamed the mighty Colorado.
d.
Many new devices had to be invented to achieve its construction, such as the drilling jumbo and a cooling system to harden the concrete.3