Which of the following HF digital modes can be used to transfer binary files?

PACTOR is a robust, Error-Free Automatic Repeat Request (ARQ) mode designed specifically to pass data securely and accurately over HF frequencies. Because it guarantees error-free delivery by requesting retransmission of any corrupted packets, it is the standard choice for transferring binary files, such as via the Winlink email system. Other modes like PSK31, RTTY, and AMTOR are primarily text-based 'chat' modes. They either lack ARQ entirely or do not have the modern, robust protocols required to reliably handle the arbitrary data found in binary files.