Which of the following statements regarding the features of blockchain technology are correct?

1. 1Records stored in the database may be made visible to relevant stakeholders without risk of alteration.
2. 2Copies of the entire database are stored on multiple computers on a network, syncing within seconds.
3. 3Consortium blockchain is a blend of public and private blockchains allowing selective data access.
4. 4Mathematical algorithms make it impossible to change or delete any data once recorded and accepted.

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