An ‘extended’ UTXO solution would need the inclusion of two features that the current UTXO model lacks:
1.To be able to keep the contract in its current state.
2.To be able to ensure that the same contract code is used throughout the transaction sequence.
Cardano’s $ADA ledger architecture extends on the UTXO model to accommodate multi-assets and smart contracts while maintaining the UTXO model’s benefits, transaction’s success or failure is solely determined by the transaction and its inputs

There are 4 types of UTXO:
1. Classic UTXO
$BTC, $BCH, $BSV, $LTC, $DOG, $DASH

2. EUTXO, which supports complex smart contracts and decentralized applications
ADA, $ERG (Ergo)

3. Privacy UTXO
Uses the discrete nature of UTXOs, combined with ring signatures, zero-knowledge proofs, or confidential transactions, to hide transaction amounts and address information
$XMR (Monero), $ZEC (Zcash)

4. Hybrid public-chain UTXO: combines DAG or multithreaded parallelization technology
$KAS, $QTUM , $CKB
Which type of UTXO is not mentioned?