Composite signature-based analysis refers to a method of intrusion detection where multiple packets are analyzed to detect an attack signature. Unlike single-packet analysis, which may only require one packet to identify an attack, composite signature-based analysis looks for patterns across several packets to determine whether an attack is underway. This method is particularly useful for detecting complex attacks that cannot be identified by a single packet's header or payload alone.

Internet Group Management Protocol (IGMP) is a communication protocol that multicasts messages and information among all member devices in an IP multicast group. However, multicast traffic is sent to a single MAC address but is processed by multiple hosts. It can be effectively used for gaming and showing online videos. IGMP is vulnerable to network attacks. Answer option A is incorrect. Internet Control Message Protocol (ICMP) is a maintenance protocol that allows routers and host computers to swap basic control information when data is sent from one computer to another. It is generally considered a part of the IP layer. It allows the computers on a network to share error and status information. An ICMP message, which is encapsulated within an IP datagram, is very useful to troubleshoot the network connectivity and can be routed throughout the Internet.
Answer option C is incorrect. BGP stands for Border Gateway Protocol. It is an interautonomous system routing protocol and is a form of Exterior Gateway Protocol (EGP). This protocol is defined in RFC-1267 and RFC-1268. It is used for exchanging network reachability information with other BGP systems. This information includes a complete list of intermediate autonomous systems that the network traffic has to cover in order to reach a particular network. This information is used for figuring out loop-free interdomain routing between autonomous systems. BGP-4 is the latest version of BGP.
Answer option D is incorrect. Exterior Gateway Protocol (EGP) is a protocol that exchanges routing information between different autonomous systems. It is commonly used between hosts on the Internet to exchange routing table information. Border Gateway Protocol (BGP) is the only active EGP.

In information security, security risks are considered an indicator of threats coupled with vulnerability. In other words, security risk is a probabilistic function of a given threat agent exercising a particular vulnerability and the impact of that risk on the organization. Security risks can be mitigated by reviewing and taking responsible actions based on possible risks. These risks can be analyzed and measured by the risk analysis process. Answer option B is incorrect. Security risks can never be removed completely but can be mitigated by taking proper actions.