The correct option is C external gills
Organisms using general body surface as their organs of gaseous exchange belong to phylums Porifera, Cnidaria, Platyhelminthes, Aschelminthes and Annelida.
Amphitrite, though an annelid, uses external gills as the organs of gaseous exchange.
Organisms using trachea for gaseous exchange insects (class Insecta of phylum Arthropoda).
Book lungs as organs for gaseous exchange are used by spiders and scorpions.