An Oracle instance is a combination of______.

A.
database files and parameter file (initialization parameter file or server parameter file)

B.
System Global Area (SGA) and background processes

C.
a listener process, server processes, and background processes

D.
System Global Area (SGA), server processes, and background processes

E.
database files, System Global Area (SGA), and background processes

Explanation:
http://docs.oracle.com/cd/A57673_01/DOC/server/doc/SCN73/ch9.htm#o instance