Question

When it's noon on the East Coast of the United States, it's only 9 A.M. on the West Coast. That may sound confusing, but it used to be much worse. Before the late 1800s, people in the United States set their clocks according to "high noon," the time when the sun was directly overhead. As a result, there were more than 300 local times across the country. But as train travel became common, the use of local times made it impossible for railroads to schedule arrival and departure times. In 1883, railroad companies came to an agreement designed to solve this problem: they divided the United States into four time zones. Though most people started using the zones, Congress didn't make them official until 1915. From east to west, these zones are called the Eastern, Central, Mountain, and Pacific time zones. In later years, two new time zones were added-one for Hawaii and one for Alaska.
Which is the BEST summary of the passage?

a
In the 1800s, people in the United States switched from using 300 local times to just four time zones. The local times were set according to "high noon" in each area. Railroad companies wanted fewer zones to help with scheduling arrivals and departures.
b
In 1915, Congress declared that the United States would have four time zones. They were called the Eastern, Central, Mountain, and Pacific zones. Two more zones were added later when the United States got larger.
c
The United States has six different time zones, so it's hard to tell what time it is. But in 1883, our country had more than 300 local times. Then people started traveling by train, and the railroad companies changed things.
d
Before railroad travel became common, the United States had more than 300 local times. In 1883, railroad companies established four time zones, which Congress later made official. With the addition of zones for Hawaii and Alaska, the United States now has six time zones.

Answer 1

d