Read the following statements.
$I.$ Preganglionic nerve fibres of $III, VII, IX$ and $X$ cranial nerves are a part of the parasympathetic nervous system.
$II.$ $V, VII, IX$ and $X$ cranial nerves are mixed nerves.
$III.$ Trochlear nerves are the largest cranial nerves.
$IV.$ Abducens nerves are motor nerves and originate from the Gasserian ganglia.
Which of the above statements are correct?

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