C) They have strong ports and a good transportation network.
Step-by-step explanation:
California, Texas, Florida and New York had strong ports and good transportation network since 1900 which made them grow economically.
The transportation network is the most important factor for the growth of economy in a country. It is seen as a major source for development of the country. An efficient transportation can reduce the costs in many economic sectors.
The government of the highly developed countries generally focuses on human resources, physical capital, natural resources and technology to increase economic growth.