If $\int _ { - 1 } ^ { 1 } f ( x ) d x = 6,$

Multiple Choice

If $\int _ { - 1 } ^ { 1 } f ( x ) d x = 6,$ then $\int _ { 0 } ^ { 1 } 2 f ( x ) d x$ is

A) -12
B) -6
C) 6
D) 12
E) Impossible to determine