Which of the following surfaces have the largest total electric flux?
A. a sphere of radius 1 m with a 1-C charge placed inside at the center
B. a sphere of radius 1 m with a 1-C charge placed inside but off-center
C. a cylinder of radius 1 m and length 1 m with a 1-C charge placed inside
D. a 1-m cube with a 1-C charge placed in the center
E. a sphere of radius 1 m with a 2-C charge placed inside and a 1-C charge placed outside