B: The Federal Government needs to respond quickly.
Congress needs to go through a long and careful process to get things done, not to mention them needing to have the majority of congress agree.
The president/executive branch of the government is made up of much less people, as well as the president himself being commander and chief of the military.
Time is very important during a national emergency, and the president can get things done quickly.
In the late 19th century, immigrants arrived in large numbers on the U.S coast from China for the primary purpose of working on the Transcontinental Railroad.
