Arrange the given steps of expiration in the sequence of events occurring first:
$I.$ Relaxation of the diaphragm and sternum
$II.$ Reduction of the pulmonary volume
$III.$ Expulsion of air from the lungs
$IV.$ Increase in intra-pulmonary pressure
Choose the correct option.

• A
  $I \rightarrow II \rightarrow IV \rightarrow III$
• B
  $I \rightarrow II \rightarrow III \rightarrow IV$
• C
  $IV \rightarrow III \rightarrow II \rightarrow I$
• D
  $IV \rightarrow II \rightarrow III \rightarrow I$