Choice A is the best answer. In these lines, the speaker compares women's previous "social and political advancement" to the "saffron tints and crimson flushes" in the sky that signal the sun will soon rise, and the "full-orbed sun of emancipation" to "the coming day." She is suggesting that the progress that has already occurred will soon be followed by the granting of voting rights and the emancipation they represent, just as the early signs of sunrise are followed by a new day.