The Gadar party was a revolutionary organization formed by Indian immigrants in the United States and Canada in the early 20th century. It aimed to overthrow British rule in India through armed struggle.

Option 1: Lala Hardayal was one of the founders of the Gadar party and played a significant role in its formation and activities.

Option 2: The correct answer is "Baba Gurdit Singh." He was not associated with the Gadar party. Baba Gurdit Singh was an Indian nationalist who organized the Komagata Maru incident, which involved a group of Indian immigrants who challenged the discriminatory laws of the Canadian government in 1914.

Option 3: Mohammad Barkatullah was a prominent member of the Gadar party and actively participated in its activities.

Option 4: Sohan Singh Bhakna was another founding member of the Gadar party and played a crucial role in its organization and activities.

In conclusion, Baba Gurdit Singh was not associated with the Gadar party, making option 2 the correct answer.