3. D is correct. A will only support 2 hosts; B only 6 and C only 14. Watch out for the minus 2 in the host calculation! Answer C creates 16 hosts on the subnet, but we lose 2 -- one for the NET ID and one for the Broadcast ID.
5. D is correct. This would copy the IOS in flash memory to a TFTP server. A and B are incorrect because the IOS is stored in flash and not NVRAM. C is incorrect because copy tftp flash would upgrade your IOS from a TFTP server rather than copy your IOS to a TFTP server.
7. B is correct. All odd-numbered hosts would have the one bit turned on in the last octet. Therefore, you need to check all hosts that have the one bit turned on (set to 1). You do not care about the other host bits. The default wild card mask for a /12 network is 0.0.15.255, but because you want to match only those hosts that have the one bit turned on, you will need a wildcard mask of 0.0.15.255.254 . A is incorrect because this would match both even and odd numbered hosts. C is incorrect because this would match all hosts from 10.48.0.0 through 10.48.255.0. D and E are incorrect because they have the wrong wildcard mask.
9. A, B and D are correct. The LCP phase is responsible for the initial link-setup and negotiating options such as compression, callback, multilink and authentication. C is incorrect because this is not a component of LCP.