Concept:Word formation is how new words are created by modifying existing ones or inventing entirely new terms. Explanation:Processes like compounding (joining two words) and conversion (changing a word’s part of speech without altering its form) are central to word formation.Other methods include borrowing, blending, clipping, and affixation, but the question's correct option lists only compounding and conversion as a pair.Both are fundamental and widely used in English. Answer:A. compounding and conversion