The Civil Disobedience Movement was a significant event in India`s struggle for independence from British rule. It was a nonviolent resistance movement led by Mahatma Gandhi.

Option 1: The Anti-Rowlatt agitation was a protest against the Rowlatt Act, which gave the British government extensive powers to suppress political dissent. Although it was a key event leading up to the Civil Disobedience Movement, it was not the starting point of the movement.

Option 2: The Dandi March, also known as the Salt Satyagraha, was a major event that marked the beginning of the Civil Disobedience Movement. Gandhi and a group of followers marched to the coastal village of Dandi to produce salt in violation of the British salt laws.

Option 3: Demonstrations against the arrival of the Simon Commission in India were a part of the larger movement but did not mark the start of the Civil Disobedience Movement.

Option 4: The no-tax campaign in the Bardoli district was also a form of civil disobedience, but it did not mark the beginning of the movement. It was a localized protest against the government`s unfair taxation policies.

Therefore, the correct answer is option 2, the Dandi March, as