It is possible to have a BT+BLE connection at node B.
For audio transmission, there are BT (not BLE) profiles available like A2DP. You can send audio data over BT to BT speaker from node B and can have a BLE connection with A. However, we do not have any code example available for voice over BLE transmission as you need node B-speaker connection in BLE mode.
On program side, I would suggest you to go through demo.watch code example in WICED SDK.
1. Just to ask one more question, is voice transfer over BLE possible. I am asking you this because I am a new person in Bluetooth.
Sure I will go through demo.watch code example in WICED SDK
2. In your reply, does BT mean BT classic, and is BT Classic same as BR/EDR.
1. Some companies provide voice over BLE feature in their products. I would suggest you to search about them in brief for more details.
2. BT classic includes Bluetooth BR, EDR, AMP technologies, so BR-EDR is normally referred to as Bluetooth classic. Some online articles might be helpful regarding this.