A instigates B to murder
C. B refuses to do so. In this case which of the following is true statement?

As per illustration clause of S. 108. S.108. Abettor.—A person abets an offence, who abets either the commission of an offence, or the commission of an act which would be an offence, if committed by a person capable by law of committing an offence with the same intention or knowledge as that of the abettor. Illustration appended to explanation 2 Explanation 2.—To constitute the offence of abetment it is not necessary that the act abetted should be committed, or that the effect requisite to constitute the offence should be caused.