The correct answer is B) verify there is room for expansion. When loading a petroleum cargo that is below average ambient temperatures, the cargo will contract and take up less volume. This means there needs to be room in the cargo tanks for the cargo to expand as the temperature rises and the cargo expands. Failing to provide this expansion room could lead to damage to the cargo tanks or other issues. The other options are not directly relevant to this specific scenario. Verifying the vents are sealed (A) and vapor baffles are installed (C) are important, but not specifically related to accounting for cargo contraction and expansion due to temperature changes.