An extranet-based VPN uses the Internet as its main backbone network, allowing users, customers, and branch offices to access corporate network resources across various network architectures. Extranet VPNs are almost identical to intranet VPNs, except that they are intended for external business partners. Answer option D is incorrect. An intranet-based VPN is an internal, TCP/IP-based, password-protected network usually implemented for networks within a common network infrastructure having various physical locations. Intranet VPNs are secure VPNs that have strong encryption. Answer option B is incorrect. A remote access VPN is one of the types of VPN that involves a single VPN gateway. It allows remote users and telecommuters to connect to their corporate LAN from various points of connections. It provides significant cost savings by reducing the burden of long distance charges associated with dial-up access. Its main security concern is authentication, rather than encryption. Answer option A is incorrect. The PPTP VPN is one of the types of VPN technology.

The Network Interface Card (NIC) operates primarily on the Physical layer of the OSI model. This layer is responsible for the actual transmission and reception of data over a network medium. The NIC provides the physical connection between the computer and the network, converting digital data into electrical, radio, or optical signals for outbound data, and vice versa for inbound data12.
Additionally, the NIC also has functionalities that extend to the Data Link layer, which is responsible for node-to-node data transfer and handling the physical addressing of packets through MAC addresses3.
Reference:
Information based on the Certified Network Defender (CND) course material and study guide.
Additional details from EC-Council's official Certified Network Defender (CND) resources and other authoritative sources on network interface cards and the OSI model132.

Volatile memory, also known as volatile storage, is computer memory that requires power to maintain the stored information, unlike non-volatile memory which does not require a maintained power supply. It has been less popularly known as temporary memory. Most forms of modern random access memory (RAM) are volatile storage, including dynamic random access memory (DRAM) and static random access memory (SRAM). A volatile storage device is faster in reading and writing data.
Answer options A and C are incorrect. Non-volatile memory, nonvolatile memory, NVM, or non-volatile storage, in the most basic sense, is computer memory that can retain the stored information even when not powered.
Examples of non-volatile memory include read-only memory, flash memory, most types of magnetic computer storage devices (e.g. hard disks, floppy disks, and magnetic tape), optical discs, and early computer storage methods such as paper tape and punched cards.