Please answer the following question: Read the following article and select the best answer. Article: A deal has been signed to turn by-products from a Scottish distillery into fuel for cars. In what is declared to be a world first, the Tullibardine distillery in Perthshire has linked up with a spin-out company from Napier University in Edinburgh. They plan to use bacteria to feed on the "leftovers" from the whisky making process. This will produce butanol which can be used to fuel vehicles. More than 90% of the stuff that comes out of a whisky distillery is not whisky. It is leftovers like draff and pot ales -- both produced in the early stages of the process. They are high in sugar and are currently used for things like fertiliser and cattle feed. Napier University's Biofuel Research Centre (BfRC) has already shown that the right bacteria can feed on those by-products to produce butanol--a direct replacement for vehicle fuel. Now the spin-out company, Celtic Renewables, and independent whisky producer Tullibardine have signed an agreement. Together they will apply the process to thousands of tons of the distillery's leftovers. Professor Martin Tangney, founder of Celtic Renewables, said "Our partnership with Tullibardine is an important step in the development of a business which combines two important Scottish industries -- whisky and renewables. This project shows that creative use of existing technologies can _ resources on our doorstep to benefit both the environment and the economy." Douglas Ross, managing director of Tullibardine, which spends PS250,000 disposing of its by-products every year, said "We are delighted to be partnering Celtic Renewables in this creative business, the obvious benefits of which are environmental. It takes a cost to us and turns it into something that has social as well as commercial value." The project is being supported by a grant from the Scottish government's Zero Waste Scotland initiative. Celtic Renewables said it eventually aimed to build a processing plant in Scotland, with the hope of building an industry that could be worth PS60m a year. Question: How do people deal with whisky leftovers at present? - They throw them away. - They use them to feed people. - They use them to feed bacteria. - They use them for crops or cattle.
Answer:
They use them for crops or cattle.