We could use the process of elimination to answer this question:
A. Electric Information Technologies - computer hardware and software, operating systems, web-based info, and apps.
B. Data Communication Networks - exactly what it sounds like: it is a network used to communicate data.
C. Digital Information Service - basically, this is storing things like books online, like if you rent an e-book, or your library went online.
D. User Interface - Dictionary Definition: "the means by which the user and a computer system interact, in particular the use of input devices and software."
So, after seeing all of these 'definitions', I think that the answer to your problem would be D.
Have an extra-fantabulous day!
