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 $q,$

National service provider $($NSP$),$ Regional service provider $($RSP$),$ and Internet service provider $($ISP$)$

None of these are correct

New system provider $($NSP$),$ Current system provider $($CSP$),$ and Order entry system provider $($OSP$)$

Net server point $($NSP$),$ Radio server point $($RSP$),$ and Internet server point $($ISP$)$