Which one of the following statements are true with reference to Russell's 'problems of philosophy'?

A. Universals are real entities which exist neither in the mental nor in the physical worlds and yet have a subsistent or logical status

B. Universals are unreal, that exist only in imagination

C. Universals are real entities, that exist in both mental and physical worlds

D. Universals are real entities that exist only in the mental world

Answer: Option A