Identify the error status of the following sentences: I. Seldom in the recent past have the impact of one month meant more in Indian foreign policy than the present one. II. In addition to sanction an aggressive foreign policy posture and military assertiveness in China's various disputes, Mr Xi announced his post-COVID-19 blitzkrieg by once again launching an attack on the so-called 'tigers' through his anti-corruption campaign.

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)