Sentence Correction

Cassowary,a flightless bird that feeds mainly on fruits but is classified a truly omnivorous,belongs to the ratite family, a group of large, wing-less topical birds that is seen only in Papua New Guinea and are not represented in any other habitat in the world.

A a group of large, wing-less topical birds that is seen only in Papua New Guinea and are
B. a group of large, wing-less topical birds that are seen only in Papua New Guinea and is
C a group of large, wing-less topical birds that are seen only in Papua New Guinea and are
D a group of large, wing-less topical birds which is seen only in Papua New Guinea and is
E a group of large, wing-less topical birds which is seen only in Papua New Guinea and which is

What is wrong with Option D?

OA C