Which one of the following words is similar in meaning to the word, 'verify' (Para-2) as used in the passage?

In the context 'work to verify whether autographs are real or fake', the word 'verify' means to confirm or establish the truth. 'Confirm' is the closest synonym. 'Clarify' means to make clearer, 'notify' means to inform, and 'discover' means to find out something new—none capture the meaning of authenticating as well as 'confirm'.