How Transactions Get Verified

Maya has one unspent output worth 0.30 BTC. She signs a transaction that pays 0.25 BTC and leaves nothing else. What happens to the other 0.05 BTC?

• It stays in Maya's wallet automatically
• It goes to the miner as the fee, because inputs minus outputs is the fee
• The transaction is invalid, because it doesn't spend the exact amount

Two valid-looking transactions spend the same unspent output. What does a node do?

• Accepts both and splits the amount between them
• Accepts the first one it sees and rejects the other as a double spend
• Rejects both and bans the sender