Sohan Singh Bhakna and Har Dayal were primarily associated with which of the following organisations?

Correct option is A

The correct answer is (a) Ghadar Party
 Sohan Singh Bhakna and Har Dayal were both prominent figures in the Ghadar Party, a revolutionary organization founded in 1913 aimed at overthrowing British rule in India through an armed uprising.
 The party was dissolved in 1948 after India gained independence.
 Its founders were Hardayal, Sohan Singh Bhakna, Santokh Singh, Baba Jwala Singh, Vashakha Singh Dandekar.
 The party launched its first newspaper 'Gadar' (Weekly) in November 1913.
 The title of the newspaper is 'Angrezi Raj Ka Dushman' (Enemy of British Raj).