The correct classification of $Balanoglossus$ is:

• A
  Chordata $\rightarrow$ Vertebrata $\rightarrow$ Enteropneusta
• B
  Chordata $\rightarrow$ Vertebrata $\rightarrow$ Pterobranchia
• C
  Chordata $\rightarrow$ Hemichordata $\rightarrow$ Pterobranchia
• D
  Chordata $\rightarrow$ Hemichordata $\rightarrow$ Enteropneusta