IP addressing version 6 (IPv6) is the latest version of IP addressing. IPv6 is designed to solve many of the problems that were faced by IPv4, such as address depletion, security, auto-configuration, and extensibility. With the fast increasing number of networks and the expansion of the World Wide Web, the allotted IP addresses are depleting rapidly, and the need for more network addresses is arising. IPv6 solves this problem, as it uses a 128-bit address that can produce a lot more IP addresses. These addresses are hexadecimal numbers, made up of eight octet pairs. An example of an IPv6 address is 45CF: 6D53: 12CD: AFC7: E654: BB32: 543C: FACE. Answer option C is incorrect. The subnet masks used in IPv6 addresses are of the same length as those used in IPv4 addresses.

Explanation:
Following are the terms with their descriptions:

A Trojan horse is a malicious software program that contains hidden code and masquerades itself as a normal
program. When a Trojan horse program is run, its hidden code runs to destroy or scramble data on the hard
disk. An example of a Trojan horse is a program that masquerades as a computer logon to retrieve user
names and password information. The developer of a Trojan horse can use this information later to gain
unauthorized access to computers. Trojan horses are normally spread by e-mail attachments. Ping sweep is a
technique used to determine which of a range of IP addresses map to live hosts. It consists of ICMP ECHO
requests sent to multiple hosts. If a given address is live, it will return an ICMP ECHO reply. A ping is often
used to check that a network device is functioning. To disable ping sweeps on a network, administrators can
block ICMP ECHO requests from outside sources. However, ICMP TIMESTAMP and ICMP INFO can be used
in a similar manner. Spamware is software designed by or for spammers to send out automated spam e-mail.
Spamware is used to search for e-mail addresses to build lists of e-mail addresses to be used either for
spamming directly or to be sold to spammers. The spamware package also includes an e-mail harvesting tool.
A backdoor is any program that allows a hacker to connect to a computer without going through the normal
authentication process. The main advantage of this type of attack is that the network traffic moves from inside
a network to the hacker's computer. The traffic moving from inside a network to the outside world is typically
the least restrictive, as companies are more concerned about what comes into a network, rather than what
leaves it. It, therefore, becomes hard to detect backdoors.