Which amendment granted women the right to vote?

The 19th Amendment to the United States Constitution specifically grants women the right to vote. Ratified in 1920, this pivotal amendment was the culmination of a long struggle for women's suffrage in the United States, advocating for equal voting rights regardless of sex. Prior to its ratification, multiple movements and campaigns were initiated by women and their allies, highlighting the importance of including women in the democratic process. This amendment significantly expanded democracy in the country by ensuring that women could participate equally in elections, shaping policies, and influencing government.

The other amendments listed do not relate directly to women's suffrage: the 15th Amendment focuses on prohibiting voting discrimination based on race, the 18th Amendment established Prohibition (banning alcohol), and the 21st Amendment repealed Prohibition. Only the 19th Amendment addresses the specific issue of voting rights for women, making it the correct answer.