In accordance with international MARPOL Annex V regulations and federal regulations under 33CFR Subchapter O, the discharge of what category of garbage is prohibited in any waters?

Correct Answer: Option B — Plastic or garbage mixed with plastic.

MARPOL Annex V and 33 CFR 151.55 strictly prohibit the discharge of all plastics into the marine environment. This includes synthetic ropes, fishing nets, and plastic garbage bags. Plastics are non-biodegradable and pose a severe, long-term threat to marine life and navigation through entanglement and ingestion.