The expiration calendar

Does a Deribit monthly option expire on the same Friday as a US monthly stock option?

• Yes, both use the third Friday
• No: Deribit uses the last Friday of the month, the US uses the third
• Yes, both use the last Friday

A friend says a 0DTE option is "just a 45-DTE trade, sped up". What is wrong with that?

• Nothing; only the time frame differs
• A 0DTE option's risk is concentrated in one day's move, with delta changing very fast, so it behaves like a different product
• 0DTE options can only be bought, never sold