Which of the following is the goal of establishing a loop-free environment?

A) This allows a switch to learn MAC addresses.
B) This allows a switch to forward only one copy of the message to the destination.
C) This allows the switch to examine the source MAC address of each frame.
D) This allows the switch to decide whether or not to forward a frame.

B
Explanation: B) STP creates a loop-free environment, which avoids broadcast storms by forwarding only one copy of a frame.