Vance had a computer crash and lost most of his personal data, including the private keys to his crypto holdings. What steps can Vance take to regain access? A. The keys will reset after 72 hours, so he will be able to access his holdings at that point. B. He can contact the coin exchange he uses, and they will be able to restore his access and reset the keys. C. Unless Vance had the information backed up, his crypto will be inaccessible for him or anyone else. D. Blockchains are a public ledger, so there are no private keys involved. There is no effect on his access.