Directions: The following question tests your ability to recognize grammar and usage errors. The sentence contains either a single error or no error at all. No sentence contains more than one error. The error, if there is one, is underlined and lettered. If the sentence contains an error, select the underlined part that must be changed to make the sentence correct. If the sentence is correct, select choice (E). In choosing the answer, follow the requirements of standard written English.

Mathematics is (A) similar to empirical sciences in that it involves an objective, careful and systematic study of (B) an area of knowledge; it is (C) different due to its method of verifying its knowledge, (D) using a priori rather than empirical methods. (E) No error