Concept:Crop insect pests are grouped by their mouthparts and the type of damage they cause to plants.Explanation:Aphids feed by piercing plant tissues and sucking out sap.Grasshoppers have chewing mouthparts and bite off plant leaves.Stemborers bore into stems with chewing mouthparts.Termites also have chewing mouthparts and feed on wood or plant material.Therefore, the insect with piercing and sucking mouthparts is the aphid.Answer:A. Aphids