If the head of a cockroach is removed,it may live for a few days because:

• A
  The supra-oesophageal ganglion of the cockroach is located in the ventral part of the abdomen.
• B
  The cockroach does not have a nervous system.
• C
  The head holds a small portion of the nervous system,while the rest is situated along the ventral part of its body.
• D
  The head contains $1/3$ of the nervous system,while the rest is located on the dorsal part of its body.