Neither.
My post #11 covers an answer.
Why care what the reason for the manner of death is? So long as the sentence is carried out, why would you care?
Gardner himself believes the firing squad is easier, with no chances for mistakes. Barring any last-minute appeals, a five-man team of executioners will take aim at Gardner just after midnight. Four of the rifles will be loaded; one will have blanks to keep anonymous the shooter who fires the bullet that kills Gardner. A black hood will be placed over Gardner’s head, and on the chest of his jumpsuit will be pinned a white cloth target.