What was the name of the headquarters of the Ghadar Party?

The correct option is Yugantar Ashram.

Step-by-Step Explanation:

1. Origin of the Ghadar Party:
The Ghadar Party was an international political movement founded by expatriate Indians to overthrow British rule in India. It was established in 1913, with key leadership from figures such as Lala Har Dayal, Sohan Singh Bhakna, and Kartar Singh Sarabha.

2. Establishment of the Headquarters:
The party set up its headquarters in San Francisco, California, United States. They named this headquarters Yugantar Ashram (literally translating to the 'Hermitage of the New Era' or 'Transition of an Age').

3. Significance of the Name:
The name was chosen to reflect the revolutionary spirit of the movement, inspired by the weekly nationalist journal Yugantar (or Jugantar) published in Bengal. The headquarters housed a printing press from which the weekly journal Ghadar was published, spreading nationalist and revolutionary ideas to Indians across the globe.