Select the correct answer. What effect do the dashes in this stanza from Dickinson’s “I heard a fly buzz—when I died” have?

I willed my Keepsakes – Signed away
What portion of me be
Assignable – and then it was
There interposed a Fly –

A.
They give a continuous rhythm to the lines.
B.
They show the connections between words.
C.
They break the rhythmic flow of the lines.
D.
They separate the insignificant information.