Mahatma Gandhi launched the Civil Disobedience Movement in 1930 as a significant phase of India's struggle for independence from British rule. This movement was marked by nonviolent resistance and aimed to challenge British authority by disobeying unjust laws. The most famous event associated with this movement was the Salt March (Dandi March), which began on March 12, 1930, when Gandhi led a group of followers on a 24-day march to the coastal village of Dandi to produce salt without paying the British tax.
Here's why the other options are incorrect:
- Option (1): 1921: In 1921, Gandhi initiated the Non-Cooperation Movement, which was an earlier phase of the Indian independence struggle. While it involved nonviolent resistance, it is distinct from the Civil Disobedience Movement.
- Option (2): 1935: This year is not directly associated with the launch of the Civil Disobedience Movement. It marks the passing of the Government of India Act, 1935, which introduced some reforms but did not relate to the start of the movement.
- Option (3): 1930: This is the correct answer, as the Civil Disobedience Movement officially began in 1930 with the Salt March.
- Option (4): 1942: In 1942, Gandhi launched the Quit India Movement, which was a more radical phase of the struggle against British rule. It came after the Civil Disobedience Movement.
Answer: $\boxed{1930}$