Which of the following is a method of attacking internet (IP) v6 Layer 3 and Layer 4?

SYN flooding (not 'SVN') is a TCP Layer 4 attack that targets TCP handshake mechanisms, but it is not specific to IPv6 and the acronym 'SVN' does not correspond to a valid networking attack term.

ICMPv6 (Internet Control Message Protocol for IPv6) is integral to IPv6 operation at Layer 3, handling neighbor discovery, error reporting, and path MTU discovery. Flooding ICMPv6 messages overwhelms network devices and consumes bandwidth, constituting a Denial-of-Service attack at Layers 3 and 4 of the OSI model. Note: The choice contains typos ('IOP' and 'flooring') but refers to ICMPv6 flooding, which is a recognized IPv6-specific attack method.

DNS cache poisoning is an application-layer (Layer 7) attack that corrupts DNS resolver caches and is not specific to IPv6 Layer 3 or Layer 4 operations.

MAC flooding is a Layer 2 (Data Link layer) attack targeting network switches by overwhelming the CAM table, which operates below Layer 3 and is not specific to IPv6.