The loss of Qandahar was a big blow to the Mughal empire from the view point of

1. Qandahar (Kandahar) was a strategically important city located on the western frontier of the Mughal empire. 2. Its location commanded the routes connecting Persia (Iran) and Central Asia with India. 3. Control over Qandahar was crucial for defending the empire from invasions from the northwest and for controlling trade routes. 4. Therefore, the loss of Qandahar, which happened definitively during Shah Jahan's reign to the Safavids of Persia, was a major blow primarily from the viewpoint of its importance as a strategic stronghold (D) and also as a buffer territory (B). However, its primary significance lay in its military and strategic value. 5. Among the given options, strategic stronghold best captures the critical importance of Qandahar.