599. Recently discovered fossil remains strongly suggest that the Australian egg-laying mammals of today are a branch of the main stem of mammalian evolution rather than developing independently from a common ancestor of mammals more than 220 million years ago.
(A) rather than developing independently from
(B) rather than a type that developed independently from
(C) rather than a type whose development was independent of
(D) instead of developing independently from
(E) instead of a development that was independent of


OA is B.