DNS servers are arranged hierarchically. How many root servers sit at the top level?

1. A DNS server holds a database of domain names and their matching IP addresses. 2. If a server does not hold an entry, it points to another DNS server that might. 3. To make that search finite, the servers are placed in hierarchical order. 4. At the top level there are 13 servers called root servers. 5. They are named with the first 13 letters A to M, which is a useful check on the number. _Source: syllabus Computer Science Class 12, Ch 10 'Computer Networks', S10.8.1 DNS Server_