Direction: Spot the grammatical errors in the given sentence. Mark the part with error as your answer. If there is no error, mark "No error" as the answer. (Ignore punctuation error)

The road widening exercise (a)/ who aims to make National Highway a four-lane highway, (b)/ poses a threat to the (c)/ fragile environment of the Himalayas. (d)/ No error (e)

[OBC (PO), 2010]