Read the following context and choose the best option to answer the question.
Context: Rap impresario Dr andre young jr dr dre . Dre 's 20-year - old son was found dead over the weekend in his Woodland Hills home , coroner 's officials said . TOXICOLOGY TEST ORDERED FOR DR . DRE 'S SON : Autopsy alone could not determine cause of death andre young jr .
Question: Why are they testing the young man 's blood ?
Options: 
A. For a work drug - screen .
B. For immunization purposes .
C. None of the above choices .
D. For a cause of death .


D