The correct option is A Amaranth
Rice, wheat, and potato all are C3 plants but amaranthus is only the C4 plant because amaranthus is found in tropical and subtropical regions, these plants show Kranz anatomy in which vascular bundles in leaves are surrounded by a layer of bundle sheath cells that contain large number of chloroplasts i.e., dimorphic. The chloroplasts of bundle cells are larger in size and are arranged centripetally while,the mesophyll cells have normal type of chloroplasts.
So, the correct option is A.