In the OSI Model, which protocols operate at Layer 4 (Transport Layer)?

1. A IP (Internet Protocol) and ICMP, which are primarily responsible for the addressing and basic logical routing of packets across the network.
2. B TCP and UDP, which provide end-to-end communication services and manage logical ports for directing traffic to specific applications.
3. C HTTP, FTP, and SMTP, which define the high-level semantic rules for how various application types should format and exchange their data.
4. D Ethernet and Wi-Fi (802.11), which handle the physical transmission of binary signals across cables or radio waves to nearby hardware devices.