What device should you add to a computer if you need to take inventory by scanning UPC symbols?

To conduct inventory by scanning UPC symbols, the most suitable device is a bar code reader. A bar code reader is specifically designed to interpret and decode bar codes, which are the series of parallel lines that represent data such as product information. When you scan a UPC (Universal Product Code) using a bar code reader, it reads the pattern and converts it into a digital format that can be processed by inventory management software.

While other devices have their specific uses, they do not serve the same purpose as effectively as a bar code reader for this task. A magnetic card reader is used primarily to read magnetic stripes found on cards, like credit or debit cards; an optical scanner is more generalized and may not be tailored to decoding bar codes specifically; and an RFID reader is focused on radio frequency identification tags, which operate on a different technology than bar codes. Therefore, for the specific task of scanning UPC symbols for inventory purposes, a bar code reader is the appropriate choice.