Why Was the Defendant's Conviction in Kennedy (No

Why was the defendant's conviction in Kennedy (No. 2) (2007) quashed in the House of Lords?

A) Because the defendant did not intend to cause the death of the victim
B) Because the chain of causation was broken by the free and informed act of self-injection by the victim
C) Because there was no unlawful act
D) Because the supply of a controlled drug is not objectively dangerous