Step 1: Sort the four bodies by whether they actually move produce across the border. MPEDA sends marine products abroad, APEDA sends agricultural and processed food items abroad, and NAFED also imports and exports notified items like pulses and edible oils under government policy.
Step 2: DMI never trades anything. Its entire job is grading farm produce for domestic markets under AGMARK and gathering market information, a purely regulatory function within India.
Step 3: Three of the four bodies have an export/import trading role, one does not. That single mismatch marks the answer. \[\boxed{\text{DMI}}\]