Why is 1928 an important year in women’s voting history?

問題： Why is 1928 an important year in women’s voting history?

選擇：Women were given the right to vote at the age of 18, the same as men.
Women were given the right to vote at the age of 25.
Women were given the right to vote at the age of 30.
Women were given the right to vote at the age of 21, the same as men.

正確答案：
4

解釋:

Women were given the right to vote at the age of 21, the same as men.