Which of the following statements about BPDU is true?

The statement that BPDU stands for Bridge Protocol Data Unit is correct. BPDUs are critical in the context of network bridges and switches, particularly in the Spanning Tree Protocol (STP), which is used to prevent loops in network topologies. BPDUs contain the information necessary for switches to maintain a loop-free network. This includes details about the bridge ID, port ID, and associated costs, allowing switches to elect a root bridge and configure their working states accordingly.

This understanding is fundamental for anyone working with Ethernet networks, as it highlights the role of BPDUs in ensuring efficient data transfer while maintaining network stability. The other statements do not accurately reflect the function or use of BPDUs, as they pertain to other technologies or functionalities not related to BPDU's definition or role in networking.