A forensic team collecting evidence from a crime scene discovers a clump of hair grasped in the victim's hand, very likely removed forcibly from the suspect. What factor would limit the usefulness of this evidence if no 'persons of interest' have been identified? A) The suspect's DNA is not on file. B) No DNA can be extracted from the sample. C) The hair doesn't exhibit clear characteristics of ethnic origin. D) The hair has been dyed so suspect's natural color can't be determined.