The Nationwide Standardization of Time-Keeping Became a Necessity for Which

The nationwide standardization of time-keeping became a necessity for which of the following reasons?

A) In the event of a national emergency, the military needed to be assured of a regularity of time from place to place.
B) Railroad scheduling required that there be a regularity of time from place to place.
C) Monetary transactions undertaken by the nation's leading financial institutions required a regularity of time from place to place.
D) The transfer of raw materials to factories and finished products to consumers required a regularity of time from place to place.