Splitting a larger OSPF area into a number of smaller areas has several advantages for network scalability and performance. Some of these advantages are:
* It increases stability by limiting the impact of topology changes within an area. When a link or router fails in an area, only routers within that area need to run the SPF algorithm and update their routing tables. Routers in other areas are not affected by the change and do not need to recalculate their routes.
* It reduces processing overhead by reducing the size and frequency of link-state advertisements (LSAs).
LSAs are packets that contain information about the network topology and are flooded within an area.
By dividing a network into smaller areas, each area has fewer LSAs to generate, store, and process, which saves CPU and memory resources on routers.
* It reduces bandwidth consumption by reducing the amount of routing information exchanged between areas. Routers that connect different areas, called area border routers (ABRs), summarize the routing information from one area into a single LSA and advertise it to another area. This reduces the number of LSAs that need to be transmitted across area boundaries and saves network bandwidth.
References: https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/7039-1.html
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13703-8.html

802.3bz is a standard for Ethernet over twisted pair at speeds of 2.5 and 5 Gbit/s. These use the same cabling as the ubiquitous Gigabit Ethernet, yet offer higher speeds. The resulting standards are named 2.5GBASE-T and 5GBASE-T.
Option A: 2.5Gb and 5Gb Ethernet ports
This is because option A shows how to identify the speed of an Ethernet port based on its name and the standard it supports. A port that supports 2.5GBASE-T or 5GBASE-T is a multi-gigabit port that can operate at speeds of up to 2.5 Gbit/s or 5 Gbit/s over twisted pair cables23.
Therefore, option A is correct.
1: https://en.wikipedia.org/wiki/2.5GBASE-T_and_5GBASE-T 2:
https://kb.netgear.com/000049004/What-is-Multi-Gigabit-Ethernet-and-how-can-I-benefit-from-using-NETGEA
https://arstechnica.com/gadgets/2016/09/5gbps-ethernet-standard-details-8023bz/

Active gateway is a first hop redundancy protocol that eliminates a single point of failure. The active gateway feature is used to increase the availability of the default gateway servicing hosts on the same subnet. An active gateway improves the reliability and performance of the host network by enabling a virtual router to act as the default gateway for that network. If you have enabled active gateway, VRRP is not required3. Active gateway is similar to VRRP in that routed traffic from the VSX node is sourced from the switch interface MAC and not the virtual MAC address (VMAC). Each active gateway sends a periodic broadcast hello packet to avoid VMAC aging on the access switches. The switch views the active gateway IP as a self IP address3. Active gateway is preferable over VRRP because with VRRP traffic is still pushed over the ISL link, resulting in latency in the network3. Therefore, VRRP and active gateway are mutually exclusive on a VLAN, and answer A is correct.
References: 1: Aruba Campus Access documents and learning resources 3: Active gateway over VSX - Aruba

The reason is that the linkup delay timer is a feature that delays bringing downstream VSX links up, following a VSX device reboot or an ISL flap. The linkup delay timer has two phases: initial synchronization phase and link-up delay phase.
The initial synchronization phase is the download phase where the rebooted node learns all the LACP+MAC+ARP+STP database entries from its VSX peer through ISLP. The initial synchronization timer, which is not configurable, is the required time to download the database information from the peer.
The link-up delay phase is the duration for installing the downloaded entries to the ASIC, establishing router adjacencies with core nodes and learning upstream routes. The link-up delay timer default value is 180 seconds. Depending on the network size, ARP/routing tables size, you might be required to set the timer to a higher value (maximum 600 seconds).
When both VSX devices reboot, the link-up delay timer is not used.
Therefore, by configuring the linkup delay timer to include LAGs 101 and 102, which are part of the same VSX device as LAG 201, you can ensure that both devices have enough time to synchronize their databases and form routing adjacencies before bringing down their downstream links.