What is the main idea of the argument presented in the text?


Standard Oil made higher profits than its competitors because it was able to buy oil for less.


Standard Oil made higher profits because it received better shipping rates from railroad companies


Standard Oil made the same profits as competing companies


here is the text:John Rockefeller might get his oil cheaper now and then, they said, but he could not do it often. He might make close contracts for which they had neither the patience nor the stomach. He might have an unusual mechanical and practical genius in his partner. But these things could not explain all. They believed they bought, on the whole, almost as cheaply as he, and they knew they made as good oil and with as great, or nearly as great, economy. He could sell at no better price than they. Where was his advantage? There was but one place where it could be, and that was in transportation. He must be getting better rates from the railroads than they were.