B) the Chinese armed forces had been removed from the city
Explanation:
The city of Nanjing was extremely powerless against Japanese attacks since Chinese political and military leader Chiang Kai-shek and General Chen Cheng pull back from the city of Nanjing alongside elite Chinese troops under substantial and consistent barrage by the Japanese Imperial Air Force. Therefore the city was absolutely unprotected and absolutely helpless against the Japanese attack.
The Allies invaded the Mediterranean because they wanted to remove Italy from axis powers. Axis powers are nations that fought in the WW2 so they basically didn't want Italy to fight in the war.
