Hot Wallets vs Cold Wallets

Which of these is a cold wallet?

• A browser extension on a laptop you only open on weekends
• A dedicated device that keeps the key inside and returns only signatures
• A phone wallet with the phone's Wi-Fi switched off

A hardware wallet connects to your phone by Bluetooth. Is it air-gapped?

• Yes, because the key never leaves the device
• No, because it has a radio connection; air-gapped means data moves only by QR code or memory card
• Yes, because Bluetooth is encrypted