Why Packet radio (AX.25) sends data in framed bundles, and each frame carries all three items. The header holds the destination and source call signs so stations know who the data is for, a frame check sequence (checksum) is appended so the receiver can tell if any bits were corrupted, and the protocol uses automatic repeat request (ARQ), meaning the receiver asks the sender to resend any frame that fails the check. That combination is what makes packet a reliable, error-free data mode.
Watch out Each individual choice is a true statement about packet, so picking just one is incomplete; the question is testing whether you know the whole frame structure.
Packet frame = address + checksum + resend: header, error check, ARQ. All three, so pick 'all'.