11788
By the start of World War II , this basic concept had developed into the idea of a " spearhead " , a dense formation of highly mobile forces that would concentrate at a single point , overwhelm them locally , and then run into the lightly defended rear areas .
 event: World War II
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
 Entities: World War II 
Answer:
 event: World War II