Which of the following statements are correct?
$I -$ Mitosis occurs in both haploid and diploid cells.
$II -$ Meiosis occurs in both haploid and diploid cells.
$III -$ Mitosis occurs only in haploid cells.
$IV -$ Mitosis occurs only in diploid cells.
$V -$ Meiosis occurs only in haploid cells.
$VI -$ Meiosis occurs only in diploid cells.

• A
  $I, VI$
• B
  $I, V$
• C
  $II, III$
• D
  $II, IV$