Answer : 3. "Persian Gulf"
Explanation :

The worst oil spill in history was not an accident, it was intentional. During the Gulf War in 1991, Iraqi troops were forced to retreat from Kuwait, so Iraqi troops opened the valves of oil wells and pipelines in an attempt to reduce the invasion by American troops. As a result, it was viewed as the largest oil spill in history. Approximately 240 million gallons of crude oil was spilled into the Persian Gulf.