The ellipses is a punctuation mark, marked by three dots '. . .' and indicates an omission of a word or phrase. While quoting material, you generally want to include only information that is relevant to your work, and omit the remaining irrelevant part. This is done by replacing it with an ellipses. It is also used in informal writing to represent the 'trailing off' of thought, like all the options given. In options A, B and C the sentences end with an ellipses '. . . ' and a full stop '.', hence they all end with four dots. The sentence in D has the ellipses but the full stop is missing. As we need to identify the option with the error, we choose option D, and A, B and C being correct, do not have to be chosen.