You need to configure a LAG between your switches.

B  is correct because duplex and speed settings are required to match on both participating devices.  According to the Juniper Networks documentation 1 , all the interfaces in a LAG must have the same speed and be in full-duplex mode. This ensures that the LAG can operate as a single logical link without any performance or compatibility issues.

C  is correct because member links are not required to be contiguous ports.  According to the Juniper Networks documentation 2 , you can group any Ethernet interfaces on a switch into a LAG, regardless of their physical location or slot number. This provides flexibility and scalability for configuring LAGs on switches.