Why were John D. Rockefeller and Andrew Carnegie sometimes called robber barons?

Question

a. They stole from the rich to give to the poor.
b. They were known for their risky investment strategy.
c. They found tax loopholes and were able to keep all their money from the government.
d. They used ruthless business tactics against their competitors.

Answer 1

d. They used ruthless business tactics against their competitors.