The outline of the principal events of urination is given below in an unordered manner:
$I.$ Stretch receptors on the wall of the urinary bladder send signals to the $CNS$.
$II.$ The bladder fills with urine and becomes distended.
$III.$ Micturition.
$IV.$ $CNS$ passes on motor messages to initiate the contraction of the smooth muscles of the bladder and simultaneous relaxation of the urethral sphincter.
The correct order of steps for urination is:

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