Correct Answer: (b) Early, during December 2021
Solution:The error in the sentence is the use of the word "during." Since the sentence specifies December 2021, it implies that Lal was appointed as the Secretary to the Lokpal at some point within that month. However, the word "during" suggests a continuous action or a period of time, which is not appropriate in this context. Hence, 'Early in December 2021' is the most appropriate answer.