What is the maximum distance that the 40GBASE-LR4 Ethernet standard can span?

B.

The 40GBASE-LR4 Ethernet standard is a type of fiber optic cabling standard that is commonly used for high-speed data center networking. It is designed to support data rates of up to 40 Gbps over a single fiber optic cable.

The maximum distance that the 40GBASE-LR4 Ethernet standard can span depends on several factors, including the type of fiber optic cable being used, the quality of the cable, and the equipment being used to transmit and receive data.

According to the IEEE 802.3 standard, the maximum reach of the 40GBASE-LR4 Ethernet standard is 10 kilometers (km) over single-mode fiber optic cable. Single-mode fiber optic cable is designed to carry light over long distances with minimal signal loss, making it ideal for high-speed data transmission over longer distances.

Therefore, the correct answer is B. 10 km. Answer A (550m), C (40km), and D (80km) are incorrect.