Refer to the exhibit. In the diagram, the switches are running IEEE 802.1s MST. Which ports are in the MST blocking state?（）

• A、GE-1/2 and GE 2/1
• B、GE-1/1 and GE-2/2
• C、GE-3/2 and GE 4/1
• D、no ports are in the blocking state
• E、There is not enough information to determine which ports are in the blocking state