Which of the following sentences contains at least one error?
a. Critics of state-mandated testing of highschoolers say it's an exercise in superficial learning and doesn't really demonstrate a student's grasp of the material studied.
b. Adrianna frequently wrote to her local newspaper to complain about grammatical errors, redundant headlines, and abrasive editorial comments.
c. Though under new ownership, the newspaper is expected to conform to the same editorial positions it has held for the last several decades.
d. Pro-business lobbyists insist that the new regulations are severe, limiting, oppressive, and will hamper economic growth.