46458
Neither Newton nor Huygens satisfactorily explained " diffraction " - the blurring and fringing of shadows where , according to rectilinear propagation , they ought to be sharp .
 person: Newton; person: Huygens
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: Newton, Huygens 
Answer:
 person: Newton; person: Huygens