A Solid Aluminum Cube Rests on a Wooden Table in a Region

Multiple Choice

A solid aluminum cube rests on a wooden table in a region where a uniform external electric field is directed straight upward.What can we say concerning the charge on the top surface of the cube?

A) The top surface is charged positively.
B) The top surface is charged negatively.
C) The top surface is neutral.
D) The top surface's charge cannot be determined without further information.