Final answer:
Optical Character Recognition (OCR) is not a scanning device but a software technology for text recognition; other options listed are actual scanning devices used in various contexts.
Step-by-step explanation:
The question asks to identify which option is not a scanning device among the following: A. Touch screen, B. Barcode reader, C. Optical Mark Reader, D. Optical Character Recognition. The correct answer is D. Optical Character Recognition (OCR). OCR is not a device; rather, it's a software technology that converts different types of documents, such as scanned paper documents, PDF files or images captured by a digital camera, into editable and searchable data.
A touch screen (A) is an input device that allows users to operate a computer by touching the display screen. A barcode reader (B) is a device used to read barcodes, typically for identifying products. An Optical Mark Reader (C) is a device used to detect marks made on certain kinds of paper, commonly used for multiple-choice test papers and surveys.