877. According to the illustrated lubricating oil system diagram, which of the labeled items would be used to verify that the gravity lube oil tank is full and overflowing

Item D, the drain pot with a gauge glass in the overflow line, indicates the gravity lube-oil tank is full and overflowing. Items N and O are located elsewhere in the system and do not verify tank level. The gravity tank is designed to overflow, so the statement that it does not ordinarily overflow is incorrect.