Grasshoppers are herbivores, and their mouthparts are the basic biting and chewing type (also known as mandibulate). They possess strong mandibles (jaws) used for cutting, tearing, and grinding solid plant material like grass and leaves.

A. piercing and sucking and D. biting and sucking are incorrect because grasshoppers do not suck fluids; they eat solid food. Piercing and sucking mouthparts are found in insects like mosquitoes and aphids, which feed on blood or plant sap.

B. sucking and chewing is incorrect because while they do chew, they do not suck. This combination (chewing-lapping) is more common in insects like bees, which chew pollen and lap up nectar.

Therefore, the correct answer is option C - Biting and chewing