In the following question some parts of the sentences have errors and some are correct. Find out which part of a sentence has an error and blacken the circle corresponding to the appropriate correct option. If a sentence is free from error, blacken the circle Corresponding toNo Erroroption in the Asnwer Sheet.Question: The ruins of the spillway are a vital clue to the epic struggle that unfold as generations of Khmer engineers coped with a water system that grew complex and unruly.

• A. No error
• B. to the epic struggle that unfold as generations of Khmer engineers
• C. The ruins of the spillway are a vital clue
• D. coped with a water system that grew complex and unruly.