what is bitcoin? group of answer choices a requirement to define an expensive computer calculation, also called mining, that needs to be performed in order to create a new group of trustless transactions (blocks) on the distributed ledger or blockchain. a way to validate transactions and achieve the distributed consensus. a type of digital currency in which a record of transactions is maintained, and new units of currency are generated by the computational solution of mathematical problems and which operates independently of a central bank. all of these choices are correct.