In which of the following is the notochord absent?

• A
  Adult $Herdmania$ and $Balanoglossus$
• B
  Adult $Herdmania$ and adult $Branchiostoma$
• C
  Larva of $Herdmania$ and $Branchiostoma$
• D
  Larva of $Herdmania$ and $Balanoglossus$