248298
Given the swamp-like conditions of trench warfare in the period , the unexploded weapons - in the form of shells , bullets and grenades - buried themselves on impact or were otherwise quickly swallowed in the mud .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities:  
Answer:
 None