Why Did the Woman Suffrage Movement Increasingly Focus Its Attention

Why did the woman 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.