The jury that convicted Boston Marathon bomber Dzhokhar Tsarnaev has begun deliberating whether he should be sentenced to life in prison or execution by lethal injection.Jurors got the case late Wednesday afternoon after federal prosecutors made their final impassioned arguments that Tsarnaev should be put to death and his lawyers asked for mercy.Death or life in prison without parole are the only two options for the jury, which last month found Tsarnaev guilty of all 30 federal counts against him in the April 15, 2013, bombing. Seventeen of those counts carry the death penalty, but the jury must reach a unanimous decision for it to be imposed.Three spectators were killed and more than 260 others wounded in the attacks near the marathon finish line.