The atmosphere in a tank is too lean if it is __________.

Correct Answer: Option C — incapable of supporting combustion because the hydrocarbon content is below the LFL (Lower Flammable Limit)

Under USCG Deck Safety, SOLAS Chapter III, and 46 CFR regulations, when addressing 'The atmosphere in a tank is too lean if it is', the mandated standard is: 'incapable of supporting combustion because the hydrocarbon content is below the LFL (Lower Flammable Limit)'.