From which structure does the link canal that supplies irrigation to D.G. Khan and D.I. Khan districts originate?

Explanation

The canal providing irrigation to the districts of D.G. Khan and D.I. Khan begins at the Chashma Barrage. Other structures listed, such as Jinnah Barrage, Sulmaki Headworks, and Trimmu Headworks, serve different regions and are not the source of this particular link canal.