Directions: The sentence below is underlined and broken into three separate parts, labelled (1), (2) and (3). One of the parts may have an error in grammar, word usage or idiom. Indicate the part having the error. If there is no error, mark (4) as your answer.

(1) Emission of greenhouse gases/ (2) and noxious chemicals/ (3) remain a cause of worry./ (4) No error