Thought is was 6, but here:
"insert a shunt into the ventricle to drain cerebrospinal fluid (to treat hydrocephalus)
insert a deep brain stimulator (DBS)
insert an intracranial pressure (ICP) monitor.
remove a sample of tissue cells (needle biopsy)
drain a blood clot (hematoma aspiration)
insert an endoscope to remove tumors."
sorry if this doesn't help or is not the answer you were looking for. good day mate!
Pretty shore the answer is D
It is the implantation of developing embryos.