Lala Hardayal and Sohan Singh Bhakna formed the Gadar Party in 1913 in San Francisco, which is the correct answer. The Gadar Party was a political organization aimed at gaining India`s independence from British rule.

Option 1, Paris, is incorrect as the Gadar Party was not formed in Paris.

Option 3, Tokyo, is also incorrect as the Gadar Party was not formed in Tokyo.

Option 4, London, is incorrect as the Gadar Party was not formed in London.

The formation of the Gadar Party in San Francisco was significant because it was led by Indian immigrants living in the United States. These individuals were inspired by the nationalist movement in India and sought to mobilize support for the cause of Indian independence from abroad. The Gadar Party played a crucial role in organizing protests, publishing literature, and raising funds for the independence movement in India.