The Development of Electric Trolleys in the Late Nineteenth Century

The development of electric trolleys in the late nineteenth century transformed the American city by

A) ending horse-drawn transportation in the city.
B) enabling cities to build upward as well as outward.
C) separating the mass transportation of the working class from the private vehicles of the wealthy.
D) enabling cities to plan streets along regular grid lines.
E) creating distinct districts devoted to residential neighborhoods, commerce, and industry.