X Intending to Kill Y by Poisoning Purchases Poison and Mixes

Multiple Choice

X intending to kill Y by poisoning purchases poison and mixes the same with a glass of milk. He gives the glass to Z to serve it to Y. Z drinks the milk and dies. Which one of the following statements is correct in this context?

A) X commits no offence as Z drinks the milk voluntarily
B) X commits the offence of abetment of suicide by Z
C) X commits the offence of death of rash or negligent act
D) X commits the offence of murder.