Final answer:
The average adult tidal volume, which is the volume of air inspired and expired during normal breathing, is approximately 500 milliliters (mL). Hence, the correct answer is D) 500 mL.
Step-by-step explanation:
The average adult tidal volume (TV) is the amount of air that is inspired and expired during normal breathing. According to the provided reference material, the tidal volume is approximately 500 milliliters (mL). This is the volume of air normally entering the lungs during quiet breathing. Therefore, the correct answer to the question is D) 500 mL.