29510
Because all dates for the Predynastic period are tenuous at best , WMF Petrie developed a system called Sequence Dating by which the relative date , if not the absolute date , of any given Predynastic site can be ascertained by examining the handles on pottery .
 person: WMF Petrie
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: WMF Petrie 
Answer:
 person: WMF Petrie