The so called Robber Barons are responsible for many issues in their practices of become major tycoons. We all know that Rockefeller was well known for his monopoly of the oil industry. This means that the answer is going to for sure be B. The ways in which they became monopolies are considered by many to be unethical, meaning that A is also correct. The other three options are not reasons for them to be called Robber Barons, although some of them did occur.
This means that the answers are A and B.
I hope this helps! :)
