43. According to Amory Lovins, "Converting to efficient lighting equipment . . . would save the U.S. electricity equal to the output of 120 large power plants plus $30 billion a year in fuel and maintenance costs." Why are quotation marks used in the sentence above? (A) It shows that the words in quotation marks are an explanation of what Amory Lovins has written. (B) The quotation marks are necessary to show that the name of a book is being discussed. (C) It signifies that the words are Amory Lovins’s and not the author's. (D) It shows emphasis.