The bail may be exonerated either (a) by the death of the defendant, (b) his imprisonment in a State prison, (c) his legal discharge from the obligation to render himself amenable to the process or (d) by his surrender to the sheriff or constable of the county in which he was arrested, in execution thereof, within twenty days after the commencement of the action against the bail or within such further time as may be granted by the court.
