The Ghadr (Ghadar) was a

The correct answer is A. The Ghadar Party was founded in 1913 by Indian emigrants on the US west coast, among them Lala Har Dayal and Sohan Singh Bhakna. Its headquarters was at San Francisco, and it published the paper Ghadar in several Indian languages. Its aim was to end British rule through armed revolt, and it drew mainly on Punjabi migrants in North America and the Far East.

• B is wrong. Singapore was the site of the planned 1915 mutiny of Indian soldiers, which Ghadarites helped organise. That was an episode, not the party's headquarters.
• C is wrong. Berlin housed the Indian Independence Committee, led by Virendranath Chattopadhyaya and Chempakaraman Pillai, during the First World War. It was a separate German-backed initiative.
• D is wrong. Ghadar was a nationalist, not a communist, body. The Tashkent-based communist groups of Indian revolutionaries emerged after 1920.

The core concept is diaspora nationalism and its links to the revolutionary movement abroad. For Mains, the Ghadar Party is a useful case for discussing how Indians overseas shaped the freedom struggle, and it sits within the Modern India syllabus on early nationalist organisations.

Trap: Aspirants often link Ghadar with Berlin or Singapore because of the war-time conspiracies. Keep the headquarters separate from the places where its plans were carried out.