Is BNB ERC20 or BEP2?

I'm quite puzzled about the nature of BNB. Could you please clarify if BNB is an ERC20 token or a BEP2 token? I've heard conflicting information about this, and it's essential for me to understand the difference as I'm considering investing in cryptocurrencies. Could you provide a brief explanation of the key differences between ERC20 and BEP2 tokens, and how that affects the functionality and use cases of BNB? Thank you for your assistance in clarifying this matter.