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)

A major computer security firm urged (a)/ the social networking site to set-up (b)/ an early-warning system after-hundreds of users were (c)/ hit by a new wave of virus attacks. (d)/ No error (e)

[CENTRAL BANK OF INDIA (PO), 2010]