Which of the phrases given below the sentence should replace the word/phrase given in underline in the sentence to make it grammatically correct? If the sentence is correct as it is given and no correction is required, select 'No correction required' as the answer.
While it is well-known that there are large-scale leakages in the public distribution system across the country, there are many states, which have manage successful reform the public distribution system and deliver foodgrains to the poor.