An uncharged aluminum block has a cavity within it. The block is placed in a region where a uniform electric field is directed upward. Which of the following is a correct statement describing conditions in the interior of the block's cavity?

• A

  The electric field in the cavity is directed upward.

• B

  The electric field in the cavity is directed downward.

• C

  There is no electric field in the cavity.

• D

  The electric field in the cavity is of varying magnitude and is zero at the exact center.