On Boy's Day,children don't have to go to school.Every family with a boy hangs up huge carpshaped flags.The flags are usually three colors:black(representing the father),red (representing the mother)and blue(representing the son). Japanese parents believe that the flags will bring their boys good luck and give them courage and power. May 5th is Japanese Children's Day. But since the festival is mainly celebrated by boys,it is usually called Boy's Day. The celebration of Boy's Day has a long history.It is said that the festival is derived from the Dragon Boat Festival in China. On this day,Japanese boys eat a special kind of rice cake. It is covered with a leaf and filled with bean paste  .Children love to eat it. And eggs on leaves are another traditional food. Japanese children are so happy that they have three festivals each year. In addition to Boy's Day,they also have Girl's Day and the 753 Festival. Girl's Day is the girl's festival on March 3. It is also called the Doll's Festival because on that day,families get a set of dolls at home for their daughters. It is celebrated because the parents want their daughters to be strong and healthy. The 753 Festival is for children aged three, five and seven years old. Japanese people think that these three ages are the luckiest ones in one's life. On that day, these children get special candies wrapped in beautiful bags.The candy is a symbol of a long and healthy life for these children. The 753 Festival falls in November. According to the passage,why do the girls in Japan always receive dolls on Girl's Day?
Because girls themselves want dolls. Because doll factories want to send dolls to girls to celebrate Girl's Day. Because parents want their daughters to be healthy. Because parents believe dolls can bring them good luck.