Rockefeller combined his many companies to create standard oil trust forming a monopoly (eliminate competition) on the oil market which question 1 options: made the price of oil drop because consumers had many options to choose from for oil led to massive riots across the us that forced rockefeller to sell the standard oil trust to the government did not affect him, the consumer, or the price of oil allowed him to set the price for oil, but hurt the consumer who paid a higher price. save

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation: