In a Data Flow Diagram (DFD),the Gane and Sarson Symbol

In a data flow diagram (DFD) ,the Gane and Sarson symbol for a process is a _____.

A) rectangle with rounded corners
B) line with a single or double arrowhead
C) flat rectangle that is open on the right side and closed on the left side
D) rectangle,which may be shaded to make it look three-dimensional