Which equation represents the relationship shown in the graph?

A coordinate grid is shown with points plotted at left-parenthesis 2 comma 4 right-parenthesis, left-parenthesis 4 comma 8 right-parenthesis, left-parenthesis 6 comma 12 right-parenthesis, and left-parenthesis 8 comma 16 right-parenthesis.
A. y = –2x
B. y = 2x
C. y = –one-halfx
D. y = one-halfx