What two descriptions best define DWDM？ （）

• A、 a WDM system that is compatible with EDFA technology
• B、 an optical technology for transmitting up to 16 channels over multiple fiber strands
• C、 an optical technology for transmitting up to 32 channels over multiple fiber strands
• D、 a technology for transmitting multiple optical signals using less sophisticated transceiver designthen CWDM
• E、 a technology for transmitting more closely packed optical signals using more sophisticatedtransceiver designs than CWDM