7964
However , they heard of a plot to ambush them by the people of Plymstock , at a bridge over the River Tavy .
 location: Plymstock; location: River Tavy
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: Plymstock, River Tavy 
Answer:
 location: Plymstock; location: River Tavy