Answer:
barcode reader is the correct answer
It is called Windows Explorer referred as explorer.exe<span />
Answer: A. Usability testing
Explanation:
Usability testing would be the correct answer because if the user interface isn't "frendly" then people won't be able to use it properly. Or if you are refering to the word friendly as looking safe, then even more so would be usability testing. Because if people don't like the fonts and styles of the user interface, they might not use it at all.
I think it’s D. Sorry if it’s wrong
