Body compensates for low oxygen availability at high altitudes by:
$I.$ Increasing $RBC$ production
$II.$ Decreasing the binding affinity of haemoglobin
$III.$ Increasing the binding affinity of haemoglobin
$IV.$ Increasing the breathing rate
$V.$ Decreasing the breathing rate
Choose the correct option for the given statement.

• A
  $I, II$ and $III$
• B
  $II, III$ and $IV$
• C
  $I, III$ and $IV$
• D
  $I, II$ and $IV$