單項(xiàng)選擇題While deploying a new switch， you accidently connect ports 3/12 and 3/18 together， creating a loop. STP detected it and placed port 3/18 in blocking mode. Why did STP not place port 3/12 in blocking mode instead？（）

A.Port 3/12 was already up and forwarding before the loop was created.
B.Port priority is based on lowest priority and lowest port number.
C.You connected the wire on port 3/18 last.
D.None of the above， it is purely random.