Answer to 2) is c) 30,000. The first official U.S. Census didn't take place until 1790, but historians estimate that 30,000 people lived in Philadelphia at the time of the signing of the Declaration of Independence.
The fact that the United States was born with a population of approximately 2.5 million, and the fact that Philadelphia was the largest city in the new country, shows just how rural a nation we were at the beginning. (One source for this information is historian David McCullough in a 2002 lecture (link -
http://www.k-state.edu/media/newsreleases/landonlect/mcculloughtext202.html) at Kansas State University.)
