Why Did the Women's Suffrage Movement Increasingly Focus Its Attention

Why did the women's suffrage movement increasingly focus its attention on a national amendment to the Constitution?

A) State campaigns were difficult and often unsuccessful.
B) Women were not going to be satisfied with local voting rights only, and they wanted a say in presidential elections.
C) Because suffrage organizations were predominantly national in scale, organizing state-level campaigns proved impossible.
D) Men were more likely to consent to women's right to vote if it was universal across the nation, not just in their state.
E) Constitutional amendments were a time-honored tradition in the United States.