The correct option is D Source of cotton
Cotton is produced from cotton plants, and not arthropods.
All the organisms with jointed appendages are a part of phylum Arthropoda. For example - butterflies, locusts, mosquitoes, etc. The organisms of this phylum have a lot of economical importance. For example - butterflies are pollinating agents. They collect nectar from the flower, which forms honey, and carry pollen grains from one flower to the other. Silk is produced from silkworm (Bombyx mori). This phylum also has a lot of vectors for a number of diseases. For example - dengue, malaria, elephantiasis, etc. The disease is caused due to the parasite carried by the vector which is transmitted to the host while the vector feeds on the host's blood. Also, locusts belong to phylum Arthropoda, which are pests and damage the crops.