The motive behind Shahjahan's Balkh campaign was to

1. The question asks for the motive behind Shahjahan's Balkh campaign (1646-1647). 2. While securing the North-West frontier (Options A and C) was a general Mughal objective, Shahjahan's campaign into Central Asia (Balkh and Badakhshan) was driven by a more ambitious goal. 3. Shahjahan harboured the ambition of reconquering the ancestral Mughal homelands of Samarqand and Ferghana (Option B) in Transoxiana, from where Babur originated. 4. The Balkh campaign was seen as a stepping stone towards this larger, albeit ultimately unsuccessful, objective. It was partly an attempt to reassert Mughal prestige in their ancestral region. 5. Expanding the empire beyond the sub-continent (Option D) is too general; the specific motive was linked to the ancestral lands.