49. DNS was modified to work simultaneously with IPv4 and IPv6 by Select only one) a. Deploying a parallel hierarchy of DNS servers for each IP stack b. Replacing each DNS A Record with a DNS AAAA Record. c. Maintaining each DNS A Record and mapping it to a DNS AAAA Record. 50. Select only true statements about routing protocols (Select more than one) a. Three types of routing protocols are: distance vector, Link State and Path Vector b. Open shortest Path First is a distance vector type protocol c. Border Gateway Protocol is best for routing across WANS to connect major networks d. Routing Information Protocol and Enhanced Interior Gateway Routing Protocol are link state protocols 51. The IETF expected that both IPv4 and IPv6 protocol stacks (dual stacks) would be deployed on networks. Select the statements that are true about IP stack deployments in the early 21" century. (Select all that apply) a. Some companies are buying released IPv4 addresses from companies that have gone to IPv6 and therefore IPv4 single stacks are being maintained. b. Dual IP stacks are the most prevalent deployment today. c. Traffic can move from IPv4 to IPv6 networks with the proper routing settings and without dual stacks d. All companies that deploy IPv6 on their networks often maintain an IPv4 stack. 52. Select the one response below that correctly defines an object model in SNMP a. The SNMP agent installed on a managed device b. The managed device itself c. The database called the MIB on a managed device d. A piece of data about a managed device