43684
His grandfather , Walter Drawbridge Crick ( 1857 – 1903 ) , an amateur naturalist , wrote a survey of local foraminifera ( single-celled protists with shells ) , corresponded with Charles Darwin , and had two gastropods ( snails or slugs ) named after him .
 person: Walter Drawbridge Crick; person: Charles Darwin
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: Walter Drawbridge Crick, Charles Darwin 
Answer:
 person: Walter Drawbridge Crick; person: Charles Darwin