Using ssh-keygen to generate a key pair and then utilizing ssh-copy-id to deploy the public key to the server's ~/.ssh/authorized_keys file for the technician's account provides a secure, passwordless authentication method that utilizes SSH keys. The private key remains with the technician, who will use it for authentication. This is considered a best practice for remote access as it provides strong encryption and avoids the risks associated with password-based logins. Option B is incorrect because using passwords for SSH access is less secure than key-based authentication. Option C is incorrect because ssh-add adds private keys to the SSH agent but doesn't configure passwordless access to remote servers. Option D is incorrect because modifying ~/.ssh/config can define client-side connection parameters but does not facilitate passwordless login by itself.