أية كلمة؟

التعريف: “A piece of software that tells the computer how to operate an external device, such as a printer, hard disk, CD-ROM drive, or scanner. For instance, you can't print unless you have a printer ______. Hard disk drivers are invisible files that are loaded into memory when you start the computer, while scanner drivers are usually plug-ins accessed from within a particular application.”

أول حرف: D

ما هي الكلمة التي يتم تعريفها؟