Answer:
C. articulation.
Explanation:
Articulation refers to a field in phonetics which studies the way that humans produce speech. Articulation refers specifically to the way humans produce sounds through the interaction of different physiological features. Therefore, it refers to the process in which humans transform the air they breath into words that can be heard. If a word is pronounced differently than intended ("going to" vs. "gonna"), this is an issue of articulation.
