What is the world's most popular open-system protocol suite because they can be used to communicate across any set of interconnected networks?

• A. TCP/IP
• B. UDP
• C. HTTP
• D. FTP

Answer: (A)

Communicating across diverse networks relies on a universal, open set of rules that everything can implement to address, route, and transport data. This protocol suite provides IP for addressing and routing, TCP for reliable connection-oriented transport, and UDP for simpler, best-effort transport, along with supporting protocols like ICMP and ARP. Because these standards are openly published and widely adopted, devices from different vendors and networks can interoperate, making it the foundation for global inter-network communication.

The other options don’t fit as the complete framework. UDP is just a transport approach that lacks built-in reliability and doesn’t address routing or inter-network addressing on its own. HTTP is an application-layer protocol used to request resources over the web, not the underlying suite that enables broad network communication. FTP is another application-layer protocol for transferring files, also not the full inter-network protocol suite.