Detective: Laser-printer drums are easily damaged, and any nick in a drum will produce a blemish of similar dimensions on each page produced by that printer. So in matching a blemish on a page with a nick on a drum, we can reliably trace a suspicious laser-printed document to the precise printer on which it was produced. Which one of the following, if true, most weakens the detective's argument?
A: Most suspicious documents are not produced on laser printers.
B: Criminals are unlikely to use their own laser printers to produce suspicious documents.
C: Drum nicks are usually so small that it requires skill to accurately determine their size and shape.
D: The manufacturing process often produces the same nick on several drums.
Choose A, B, C or D as your solution.
D