Which best explains how railroad companies are able to standardize there timetables in 1883?

a) by combining into a single railway company

b) by working together voluntarily

c) by unionizing their labor forces

d) by complying with federal legislation

The answer is B. By working together voluntarily.

Explanation: Standardizing time zones was a voluntary act of humans coming together to solve problems that existed in the 1800's since each small region or town had their on local time. With railroads advancing and people getting all mixed up as they moved from city to city with times changing in every city they stopped by, especially with railroad transport becoming shorter and shorter, this brought a lot of confusion, as one would imagine. So the need for people especially in Northern America,( united States and Canada) clearly saw the need to have common time zones to ease transit times and lessen or eliminate the time confusions that were stemming up from each transit town having its own local time.

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: