The serpent that did sting thy father’s life
Now wears his crown.
Passage: 'Tis given out that, sleeping in my orchard,
A serpent stung me. So the whole ear of Denmark
Is by a forgèd process of my death
Rankly abused. But know, thou noble youth,
The serpent that did sting thy father’s life
Now wears his crown.
Basically saying: Hamlet was sleeping and a snake bit me.
It was actually C that killed me.