Except skin, other physical barriers which also helps to prevent the entry of the microorganisms are

$I.$ mucus coating of the epithelium lining the respiratory

$II.$ gastrointestinal tracts

$III.$ urogenital tracts

Choose the correct option

• A

  $I\; and \;II$

• B

  $I \;and\; III$

• C

  $II\; and\; III$

• D

  $I, II\;and\; III$