Alice wants to send an encrypted email to Bob using public key encryption. What process will Alice use?

Alice sends the public key to Bob, encmpts the email with her private key. Bob unencrypts the email with his public key sent from Alice.

Public key crypto requires the use of a single key. Both keys are distributed securely and Bob opens the email with the key from a key distribution center $($KDC$)$

Alice encrypts the email with her private key and Bob unencrypts the email with his public key.

Alice encrypts the email with her public key and Bob unencrypts the email with his private key.

None of the above