Comprehensive and Detailed Explanation (aligned to N10-009):
802.1X provides port-based Network Access Control (NAC), requiring authentication (often through RADIUS) before granting access. This is the standard for enterprise authentication on both wired and wireless networks.
A). 802.1Q defines VLAN trunking.
C). 802.3bt defines higher-power PoE.
D). 802.11h deals with spectrum management in wireless.
References (CompTIA Network+ N10-009):
Domain: Network Security - NAC, 802.1X authentication.

Cross talk can often be caused by improper termination of cables. The first step in troubleshooting should be to inspect the connectors for any wires that might be touching or exposed. Ensuring that all wires are correctly seated and that no conductors are exposed can help reduce or eliminate cross talk. This step should be taken before attempting to re-terminate the connections or check for other sources of interference.References:
CompTIA Network+ study materials.

Security groups in cloud environments act as virtual firewalls for VM instances, controlling inbound and outbound traffic based on specified rules.
From Andrew Ramdayal's guide:
"Network security groups are used to control inbound and outbound traffic to cloud resources within a VPC.
They act as a virtual firewall for associated instances..."

NAT (Network Address Translation) allows multiple private IP addresses to share a single public IP when accessing the internet. This conserves public IPs and provides basic security by hiding internal addresses.
B). BGP is a routing protocol.
C). OSPF is a link-state IGP.
D). FHRP provides redundant gateways, not IP sharing.
References (CompTIA Network+ N10-009):
Domain: Networking Concepts - NAT, PAT, private-to-public IP mapping.

Smishing (SMS phishing) occurs when attackers send fraudulent text messages pretending to be a trusted source, tricking the victim into giving up sensitive credentials. Since this came via text message, it qualifies as smishing.
A). DNS poisoning corrupts name resolution.
B). ARP spoofing manipulates MAC-to-IP mappings.
C). Vishing is phishing via voice calls, not text.
References (CompTIA Network+ N10-009):
Domain: Network Security - Social engineering, phishing types (smishing, vishing, spear phishing).