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The British Army mechanised all cavalry regiments between 1929 and 1941 , redefining their role from horse to armoured vehicles to form the Royal Armoured Corps together with the Royal Tank Regiment .
 British Army, Royal Armoured Corps, Royal Tank Regiment
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 British Army, Royal Armoured Corps, Royal Tank Regiment