During the hemodialysis process:
$I.$ Blood is drained from a convenient artery and an anticoagulant (heparin) is added.
$II.$ Removal of nitrogenous waste from the blood occurs.
$III.$ Blood is passed through a coiled porous cellophane membrane tube bathing in dialysis fluid.
$IV.$ Blood is mixed with anti-heparin and passed into a vein.
Arrange the steps in the correct sequence.

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