All we have to fear is fear _______.

The word 'fear' is a singular abstract noun and will therefore be followed by an appropriate reflexive pronoun. The word 'ourselves' is used for collective inclusive nouns, such as a group of people. The word 'myself' is a reflexive pronoun for a person referring to themselves. The word 'itself' will be used for abstract nouns such as 'fear', and is the correct answer here. The word 'yourself' is a reflexive pronoun for a second person. The correct answer is option C.