Body compensates low oxygen availability at high altitudes by

$I.$ increasing $RBC$

$II.$ decreasing binding affinity of haemoglobin

$III.$ increasing binding affinity of haemoglobin

$IV.$ increasing breathing rate

$V.$ decreasing breathing rate

Choose the correct option for given statement

• A

  $I, II$ and $III$

• B

  $II, III$ and $IV$

• C

  $I, III$ and $IV$

• D

  $I, II$ and $IV$