The correct answer is option 3, `Komagata Maru` was a ship. The Komagata Maru was a steamship that was hired by a group of Sikh immigrants from British India to travel to Canada in 1914. They intended to challenge the discriminatory immigration laws of the time that restricted immigration from India. However, upon arriving in Canada, the passengers were denied entry and the ship was forced to remain in Vancouver harbor for two months. Eventually, the ship was forced to return to India, and upon reaching Kolkata, clashes broke out between the passengers and the British authorities resulting in many deaths and arrests. The Komagata Maru incident is seen as a significant event in the history of Indian diaspora and the struggle against discrimination.