Which of the following statement sequences is correct to initiate expiration? (i) Relaxation of external intercostal muscles and return of diaphragm and sternum to their normal position. (ii) Air expelled from lungs. (iii) Volume of thorax decreases. (iv) Intrapulmonary pressure increases.

• A.  (i), (iii), (iv), (ii)  
• B.                    (ii), (iv), (iii), (i)
• C.  (iv), (iii), (ii), (i)  
• D. (i),(ii), (iii), (iv)