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.

(A) Fields Medal, sometimes described as the Nobel Prize of Mathematics, is awarded (B) once in every four years to as many (C) as four young awardees at a time, (D) who are talented mathematicians. (E) No error