Implementing directional antennas on AP1 and AP2 is the best step for the technician to take to resolve the issue of undesired RSSI in the parking lot and other exterior areas near the building. RSSI stands for received signal strength indicator, which is a measure of how well a device can receive a wireless signal from an access point (AP). An AP is a device that provides wireless connectivity to a network. An antenna is a device that radiates or receives electromagnetic waves. A directional antenna is an antenna that focuses the wireless signal in a specific direction, resulting in higher gain and longer range. By using directional antennas on AP1 and AP2, which are located near the exterior walls of the building, the technician can reduce the wireless signal leakage to the outside areas and improve the wireless coverage inside the building. Reference: [CompTIA Network+ Certification Exam Objectives], What Is RSSI and How Does It Affect Wireless Networks?, Directional Antennas: Everything You Need to Know

The question asks about the command that an engineer should send before entering the DNS name to verify the external record for SMTP traffic, which is the mail exchange (MX) record.
The MX record is a type of DNS resource record that specifies the mail server responsible for accepting email messages on behalf of a domain name.
To query the MX record using the nslookup command, the engineer should first set the query type to MX using the command set querytype=Mx or set type=Mx.
The other options are not correct, as they do not set the query type to MX:
set type=A sets the query type to A, which is the address record that maps a domain name to an IP address.
ls -d company-mail.com lists all DNS records for the domain company-mail.com, but does not specify the query type.
set domain=company.mail.com sets the default domain name to company.mail.com, but does not specify the query type. Reference:
CompTIA Network+ N10-008 Study Guide, Chapter 3, Section 3.4, DNS Concepts, page 1441 Professor Messer's CompTIA N10-008 Network+ Course Notes, Section 3.4, DNS Concepts, page 242 Professor Messer's CompTIA N10-008 Network+ Training Course, Video 3.4 - DNS Concepts, 9:00 - 10:003

A layer 3 switch is a device that can perform both switching and routing functions. It can forward packets based on the destination IP address, which is the information used to identify different subnetworks. A layer 3 switch can also create and manage multiple VLANs, which are logical subnetworks within a physical network. Therefore, a layer 3 switch can allow communication between two different subnetworks.
A router is a device that connects multiple IP networks and forwards packets based on the destination IP address. A router can also perform network address translation (NAT), which allows devices with private IP addresses to communicate with devices with public IP addresses. Therefore, a router can allow communication between two different subnetworks, especially if they use different address spaces.
An IDS (intrusion detection system) is a device that monitors network traffic and detects malicious or anomalous activities. An IDS does not forward packets or allow communication between subnetworks, but rather alerts the network administrator or takes preventive actions when a threat is detected.
An access point is a device that allows wireless devices to connect to a wired network. An access point does not forward packets or allow communication between subnetworks, but rather acts as a bridge between the wireless and wired segments of the network.
A layer 2 switch is a device that forwards frames based on the destination MAC address, which is the information used to identify devices within the same subnetwork. A layer 2 switch does not perform routing or network segmentation, and therefore cannot allow communication between different subnetworks.
A media converter is a device that converts signals between different types of media, such as copper and fiber. A media converter does not forward packets or allow communication between subnetworks, but rather enables devices with different physical interfaces to connect to the same network.
Reference:
Network Devices
Routing and Switching Essentials
CompTIA Network+ N10-008 Study Guide, Chapter 2: Devices and Infrastructure, pages 58-63, 72-75.

Enhanced Interior Gateway Routing Protocol (EIGRP) uses bandwidth and delay as its primary metrics to determine the best path for routing traffic. EIGRP is an advanced distance-vector routing protocol, which is proprietary to Cisco systems, making it highly efficient in a variety of network designs. It can also utilize load, reliability, and maximum transmission unit (MTU) as additional metrics, but bandwidth and delay are the primary considerations in its composite metric calculation. Other protocols listed, such as RIP, OSPF, and BGP, use different metrics like hop count (RIP) and cost based on link state (OSPF), or make decisions based on path attributes and policy (BGP).

The 802.11n standard is the most suitable option for this scenario. It operates in both the 2.4GHz and 5GHz frequency bands, providing better performance and higher data rates compared to older standards like 802.11b and 802.11g.
802.11n (also known as Wi-Fi 4): This standard supports multiple-input and multiple-output (MIMO) technology, which allows for better coverage, increased throughput, and improved reliability. It operates in both the 2.4GHz and 5GHz frequency bands, making it compatible with a wide range of devices. The 5GHz band provides less interference and higher data rates, making it suitable for modern networks.
802.11b: This older standard operates only in the 2.4GHz band and has a maximum data rate of 11 Mbps. It is not recommended for high-performance networks.
802.11g: This standard also operates in the 2.4GHz band and offers a maximum data rate of 54 Mbps. While it is faster than 802.11b, it is still not as efficient as 802.11n.
Reference:
Professor Messer's Network+ Study Guide
CompTIA Network+ N10-008 Study Guide