If $100$ megaspore mother cells undergo meiosis,then how many megaspores are formed $(a)$,how many degenerate $(b)$,and how many remain functional $(c)$?

• A
  $a- 400, b- 200, c- 200$
• B
  $a- 200, b- 0, c- 200$
• C
  $a- 400, b- 0, c- 400$
• D
  $a- 400, b- 300, c- 100$