The correct answer is A) less harmful to sea life than lighter oils. Heavy fuel oils, also known as bunker oils, are generally less toxic and less harmful to marine life compared to lighter refined oils like gasoline or diesel. This is because heavy fuel oils have larger, more complex hydrocarbon molecules that are less bioavailable and harder for marine organisms to absorb. Additionally, heavy oils tend to form thicker, more viscous slicks on the water's surface, which can be more easily contained and cleaned up compared to the lighter, more volatile refined oils. The other options are incorrect - B) is false as heavy oils are less harmful, C) is incorrect as heavy oils can still pose a significant threat to the marine environment, and D) is inaccurate as heavy oils can actually be more difficult to clean up compared to lighter refined oils.