Where is the B button in your keyboard for gba emulator?

In a Game Boy Advance (GBA) emulator, the B button is typically mapped to a specific key on your keyboard, often the "Z" or "X" key, depending on the emulator's configuration. You can usually customize these controls in the emulator's settings under the "Input" or "Controls" section. Make sure to check the documentation or help section of your specific emulator for the exact default mappings and how to change them if needed.