This voting system was used in georgia's primaries from 1917 to 1962, allotting votes by county in party primary elections and giving a great amount of power to rural areas at the expense of urban population centers.

County Unit System..

Explanation:

The county unit system was a voting system used by the U.S. state of Georgia to determine a victor in statewide primary elections from 1917 until 1962.

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:

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.