The Internet Is a Hierarchical Structure Linking Different Levels of Service

The Internet is a hierarchical structure linking different levels of service providers whose millions of devices supply all the interconnections.The three levels outlined in the book from the top down include ________.

A) new system provider (NSP) , current system provider (CSP) , and order entry system provider (OSP)
B) national service provider (NSP) , regional service provider (RSP) , and internet service provider (ISP)
C) net server point (NSP) , radio server point (RSP) , and internet server point (ISP)
D) None of these are correct.