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Grandpa is never identified on-screen with a proper name , so we never learn whether he is Mr. Mason or Mrs. Mason 's father – both refer to him simply as " Grandpa " in much the same way as the parents of comic strip characters – such as The Beano s Dennis the Menace , for example – call each other " Mum " and " Dad " .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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