Directions: The sentence contains either a single error or no error at all. If the sentence contains an error, select the one underlined part that must be changed to make the sentence correct. If the sentence is correct, select choice (E). In choosing the answers, follow the requirements of standard written English.

(A) A recent independent study proposed that (B) the most effective way (C) to improve quality of public education is (D) to rise teacher's salaries. (E) No error.