Final answer:
Industrialists of the late 1800s, such as Andrew Carnegie and John D. Rockefeller, spurred economic growth by establishing large corporations. option b.
Step-by-step explanation:
The major contributors to economic growth during the industrial boom of the late 1800s were industrialists who established large corporations. Innovations such as the assembly line and advances in technology helped to transform the agricultural and industrial landscape of America.
Men like Andrew Carnegie and John D. Rockefeller built vast enterprises that utilized these innovations and pushed America toward rapid economic expansion.
While their methods sometimes mirrored those of the so-called "robber barons", their contributions had a significant impact on transforming the country into an industrial and urbanized society.
Corporations allowed for large-scale production and national distribution, which was key to economic growth. This involved not only technological advancements but also new business models and approaches to marketing and management.
The shift from rural to urban population centers was driven by the need for labor in these growing industries, changing the demographic makeup of the country and spurring further economic growth.
So option b is correct answer.