An essential difference between the operating system that runs a typical desktop computer and the operating system that runs a typical PDA is that …….

(A) the desktop OS has a graphical user interface
whereas the PDA OS does not.
(B) the desktop OS can run several programs
simultaneously whereas the PDA OS cannot.
(C) the desktop OS manages hardware resources
whereas the PDA OS does not.
(D) the desktop computer has an OS whereas a
PDA does not