Directions: The given sentence is divided into four parts A, B, C, and D. Choose the part that contains an error as your answer. If the sentence is error-free, mark 'No error' as your answer.

As the political negotiations unfolded on the international stage, (A) no sooner did diplomats reach a tentative agreement (B) when a cascade of intricately interwoven issues emerged, (C) necessitating a delicate balance of compromise and strategic manoeuvring. (D)