which effort was the first attempt to regulate the monoploizing and pricing practices of the railroad?

The effort that was considered first attempt to regulate the monopolizing and pricing practices of the railroad is:

Laws passed by state legislatures regulating the monopolizing and pricing practices of the railroad corporations.

Explanation:

The railroad has played a vital role in the history of industrialization. The two industries, that were most expanded as a result of transcontinental railroad, were mining and agriculture. But the wealthy railroad barons were doing some practices of practice. So, the efforts were made to mitigate these issues. The laws were passed by the stated legislatures in order to regulate the monopolizing and pricing practices of the railroad. As a result of these efforts, things become better and it solved my problems gradually.