Multiple choice Which of the following acts as a photosensitizer? Xylenol orange Xylene cyanol Victoria Blue BO Water blue Reveal answer Fill a bubble to check yourself C Correct answer Explanation Victoria Blue BO, also known as C.I. Basic Blue 7 and C.I. 42595, is a chloride salt of a synthetic blue triarylmethane dye. Its chemical formula is C33H40N3Cl. It has the appearance of a reddish blue powder. It is a photosensitizer.