Concept:
The Mughal state invested heavily in agricultural infrastructure to boost land revenue. The maintence and expansion of artificial irrigation systems, such as wells, reservoirs, and extensive cals, were key to bringing arid lands under cultivation.
Step 1: Alyzing historical cal engineering under the Mughals
The Shah har was origilly a cal system built during the Sultate era. Over time, it accumulated silt and fell into disuse.
Step 2: Identifying the ruler responsible for the repair work
During the seventeenth century, the Mughal Empire experienced a golden age of architecture and civil engineering under Emperor Shah Jahan. Recognizing the irrigation needs of the Punjab region, Shah Jahan ordered his engineers, led by the noble Ali Mardan Khan, to clean, restore, and extend this vital water channel. The renewed cal brought water from the Ravi River to irrigate imperial gardens and agricultural fields, significantly boosting regiol productivity. Thus, the correct option is Shahjahan.