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.