Which of the following innovators was most responsible for making the United States a world economic power?

A.

Guglielmo Marconi

B.

Samuel Morse

C.

Heinrich Hertz

D.

Andrew Carnegie

Is it B?

First, Heinrich Hertz was German and Guigiermo Marconi was Italian - they were not Americans, so we can reject those options. Samuel Morse did important contributions to communications, but the best answer is Andrew Carnegie - Carnegie was a successful industrialist and he also directly supported American Industry, he himself was very rich but he also generously donated to charities.