Under federal regulations, what minimum level of Blood Alcohol Content (BAC) constitutes a violation of the laws prohibiting Boating Under the Influence of Alcohol (BUI) on commercial vessels?

Correct Answer: Option D — .04% BAC

46 CFR § 16.201 and 33 CFR § 95.02 establish that a Blood Alcohol Content of 0.04% or higher constitutes a violation for commercial mariners. This strict standard is enforced to ensure the safety of navigation and the protection of the marine environment by prohibiting impairment while on duty.