$I.$ Annual rings are formed as a result of seasonal environmental conditions.
$II.$ Tracheids/vessel elements are larger during periods when water is abundant.
$III.$ Tracheids/vessel elements have thicker walls during periods of water deprivation.
$IV.$ Wood formed in previous years is always darker than newer wood.
Select the combination of correct statements from the options given below.

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