1. Binance Chain (BNB) When i choose this transfer network it says; The address does not match the currently selected network, it is recommended that you switch to another network.
2. Binance Smart Chain (BSC) When i choose this option it asks to confirm Yes/No if the platform or application you are withdrawing to supports the BSC network.
This option means that you'll send a Bitcoin-pegged token using other blockchain networks, so it is not really Bitcoin per see. I think you'll have to read further if you want to know what's those tokens are about.
See the previous reply above since you're trying to do a P2P transfer (but it seems like you'll need their e-mail or other details instead).