At railroad crossings, you must stop at least from the nearest rail if a flagger is warning of an oncoming train.

The correct answer is: 15 feet

Explanation:

The railroad crossing, also known as the level crossing, refers to the intersection of a road and railway line. Generally, an employee of the railroad called the flagman, indicates the approaching train by waving a red colored flag or lantern to clear the railway tracks and stop the traffic.

When signaled by the flagman, you should stop at least 15 feet from the nearest railway track.

sectionalism continues to divide the nation as the question of slavery being allowed in the mexican cession became a problem. -the results of the mexican war spark secession in the south because the north did not want to allow slavery in the territories won.