What will be the value of $a?

After performing the following operations: $a = array(‘a’, ‘b’, ‘c’); $a =
array_keys(array_flip($a)); What will be the value of $a?

A.
None of the above

B.
array(‘a’, ‘b’, ‘c’)

C.
array(‘c’, ‘b’, ‘a’)

D.
array(2, 1, 0)