The correct answer is option B. This sentence is an example of Oxymoron.
Oxymoron is a figure of speech that consists of two opposed elements. In this case, "Faith" and "Unfaithful" are two contradictory concepts that are connected in the same sentence. The same happens with "falsely" and "true".
Oxymorons may present a paradox but it is not the same concept. Another example of Oxymoron is: "controled chaos".