Which is the most likely explanation for the impact of world war i on the growth of voting opportunities for women?

women served with courage on the battlefields, and they sought to be rewarded by being granted the right to vote.
new job opportunities opened up for women during the war, allowing them to take on new roles and gain public appreciation.
the large number of battlefield casualties resulted in not enough voters being available to take part in elections.
legislators around the world agreed that if women had been able to vote, world war i would never have happened.