The term "segregated ballast" is defined in the U.S. regulations as ballast water introduced into which of the following?

Correct Answer: Option B — tank that is completely separated from the cargo oil and fuel oil systems

Segregated ballast, as defined in 33 CFR 157.03, refers to ballast water held in tanks dedicated solely to ballast. These tanks must be completely separated from the cargo oil and fuel oil systems to prevent cross-contamination, ensuring that the discharged ballast remains free of oil and other pollutants.