What is the definition of an STP designated port?

A. A port that is determined to have the lowest cost to the network segment and placed in a forwarding state.
B. A port that is determined to have the lowest path cost to the root bridge and placed in a forwarding state for a network segment.
C. A port that is determined to have the highest path cost to the root bridge and placed in a blocking state for a network segment.
D. A port that is determined to have the highest cost to the network segment and placed in a forwarding state.

A. The designated port is the port with the lowest cost of the redundant links to the network segment. The adjacent port is normally the root port leading back to the root bridge.