Identify the segment in the sentence that contains a grammatical error: He is considered as (1) / an authority on the subject (2) / owing to his years of experience (3) / and extensive research. (4)

The Dandi March, also known as the Salt Satyagraha, was led by which influential leader?

Which act formally granted independence to India, marking the end of British rule?

Who was the key figure in establishing the Indian National Congress?