When attempting to send a file to another user securely with GPG, which of the following actions must be done?

Encrypting with your own public key would mean only you could decrypt it with your private key, not the intended recipient.

GPG encryption uses asymmetric cryptography where data encrypted with a public key can only be decrypted with the corresponding private key. Therefore, to ensure only the intended recipient can read the file, it must be encrypted using their public key, which they share freely.

Encrypting with your private key is used for digital signing to prove authenticity and integrity, not for confidentiality to another user.

You do not have access to their private key; if you did, it would defeat the purpose of asymmetric encryption.

Signing the file with your public key is incorrect; you sign with your private key, and the recipient verifies with your public key, which addresses authenticity and integrity, not confidentiality for sending a secure file.