Which were results of the construction of the transcontinental railroad chose all the correct answers .

a . the railroad allowed the Great plains to become the most densely populated region of the country

b . The railroad led to the creation of uniform time zones in order to make scheduling trains easier .

c . the rail road made the plains indians wealthy because they owned the land it crosses .

d . the railroad cut travel time between the east and west coast of the united states by many weeks .

PLEASE HELP COOSE ALL THE CORRECT ANSWERSS :))