Please choose the correct answer to the question: Some of the new cars being made can run on a renewable fuel that is made mostly from corn. Scientists are developing even more renewable fuels to replace gasoline. Why are renewable fuels most likely becoming more important?

Answer1: Renewable fuels release less energy. Answer2: Car fuel tanks are being made smaller. Answer3: The demand for gasoline is decreasing. Answer4: Nonrenewable fuel supplies are limited.

Answer format: answer1/answer2/answer3/answer4