Researchers trying to make it possible to trace counterfeit documents to the printer that produced them are (i)____________ the fact that the rotating drums and mirrors inside laser printers are imperfect devices that leave unique patterns of banding in their output. Although these patterns are (ii)____________ to the naked eye, they can be (iii)____________ and analyzed by computer programs that the researchers have spent the past year devising. A. exploiting B. invisible C. detected D. facing E. obvious F. implemented G. manipulating H. unappealing I. generated