The correct answer is B) Black and white corrosive placard. This is because the tank container previously carried sodium hydroxide, which is a corrosive material. Even though the container is now empty, it has not been cleaned, so it still contains residues of the corrosive material. According to hazardous materials regulations, an empty container that previously held a hazardous material must display the appropriate hazard placard until it has been thoroughly cleaned and purged. The other options are incorrect. Option A is incorrect because a residue label is not required for an empty container. Option C is incorrect because an empty container with residues must display a placard. Option D is incorrect because an "empty" placard is not appropriate for a container that still has corrosive residues.