Which of the following sentences contains at least one error?

a. Standardized testing in our schools provides vital feedback on student performance, at the risk of turning the classroom into a test preparation environment.

b. The small number of factual errors in the local newspaper can in part be attributed to the persistent supervision of the associate editor.

c. The community is equally divided between animosity towards, and agreement with, the editorials written by the new columnist at the paper.

d. Any new regulations must balance the desires of business to remain unrestrained and the public to be protected from questionable business practices.