The correct answer is A) by using wing tanks near the longitudinal center, discharging as necessary. When discharging a tanker, the list can be controlled by using the wing tanks near the longitudinal center of the vessel. This allows for the even distribution of the remaining cargo, maintaining the vessel's stability and preventing excessive heel or list. The other options are not the most effective ways to control list during discharge operations. Using a center tank near the bow or the after peak tank would not provide the same level of longitudinal stability as the wing tanks near the center of the vessel.