How did the practice of rebating part of the freight charge work?

1. 1. A rebate returned part of the charge already paid, so it lowered the real price of carriage. 2. 2. The rebates went to large shippers, not to every customer. 3. 3. Small shippers paid the full published rate and so carried a higher cost per load. 4. 4. That disadvantage is exactly what the practice is said to have created. 5. 5. Equal rates per mile would remove the abuse, so the third option describes what reform aimed at, not the practice. 6. 6. Nothing here involves a payment to the state, so the fourth option is unconnected. _Source: An Outline of American History (U.S. Information Agency, 1990, public domain), section CITIES AND PROBLEMS MULTIPLY_