दिए गए अंग्रेजी वाक्य के उस भाग को चुनें जिसमें त्रुटि है। यदि कोई त्रुटि नहीं है, तो 'No error' चुनें। The young learners were divided on groups, according to their abilities.

Find the part of the sentence that contains a grammatical error: (1) Scarcely had the newly appointed Director of Intelligence assumed her post / (2) when a sophisticated cyber-espionage campaign was detected / (3) within the high-security servers of the national defense agency, / (4) prompted an immediate and total lockdown of all external communication channels.

Find out which part of the following sentence contains a grammatical/contextual error: I congratulate you (A)/ on your success (B)/ in the examination (C)/ that never happened last week (D)