Which of the following is MOST likely to result in data loss?

Which of the following is MOST likely to result in data loss?

A.
Accounting transferring confidential staff details via SFTP to the payroll department.

B.
Back office staff accessing and updating details on the mainframe via SSH.

C.
Encrypted backup tapes left unattended at reception for offsite storage.

D.
Developers copying data from production to the test environments via a USB stick.