The correct answer is B) Stop loading. When you notice oil on the water near the barge during bulk oil loading, the first and most critical action is to stop the loading operation immediately. This is because continuing to load oil could exacerbate the spill and cause further environmental damage. The regulations require the loading to be stopped as soon as a potential spill is detected, before notifying the Coast Guard or other authorities. The other options, while important, are secondary steps that should be taken after stopping the loading. Notifying the Coast Guard (A) and the terminal superintendent (C) are necessary to report the incident, but the primary concern is to halt the loading to prevent further spillage. Searching the vessel for leaks (D) can be done, but only after the loading has been stopped.