Which of the following is the best way to securely store an encryption key for a data set in a manner that allows multiple entities to access the key when needed?

Key escrow is the best option because it involves a trusted third party holding a copy of an encryption key. This allows multiple authorized entities (e.g., an organization and a government agency) to access the key under predefined conditions, ensuring data recoverability and compliance while maintaining security. Public key infrastructure (PKI) manages digital certificates and public/private key pairs, but it doesn't inherently provide a mechanism for multiple entities to access a single encryption key for a dataset. Open public ledger (like blockchain) is a distributed database for transactions, not a secure storage mechanism for private encryption keys. Public key encryption is a method of encryption using public and private keys, but it doesn't address the secure storage and multi-entity access requirement for a single key.