Please answer the following question: Bill Gates, the founder of Microsoft and one of the richest people in the world, is now making efforts to reinvent the toilet. Gates has donated a big part of his wealth to charity. Now his charitable organization, the Bill & Melinda Gates Foundation, is looking for future toilets that can improve the living conditions of millions of people. The flush toilet we use today was invented in 1775. While it works well in getting rid of our waste, it also uses a lot of water and needs a costly sewage system . Besides, it's not necessarily practical for the developing world. In some developing countries, lack of toilets leads to poor hygiene ,and _ could kill people. According to the World Health Organization, 1.5 million children under the age of five die each year because of hygiene problems. Last year, the Gates Foundation gave money to eight universities around the world and asked them to start inventing the toilet of tomorrow: a toilet that uses little or no water is cheap and easy to fix, and is safe and hygienic. At the " Reinvent the Toilet Fair " competition recently held in Seattle, twenty-eight designs were displayed. The winners, from the California Institute of Technology , were awarded a $ 100,000 prize by the Gates Foundation. "We couldn't be happier with the response that we've gotten," Bill Gates said at the event. Many of the new designs would not only greatly improve hygiene in the developing world, but also help change the dependence on traditional flush toilets in developed nations, he said. How many designs were displayed at the "Reinvent the Toilet Fair"? A) Eight. B) Eighty. C) Eighteen. D) Twenty-eight.
A:
D