Explanation:

- Option 1: Indus

- Correct Answer

- The Diamer Basha Dam is indeed being constructed on the Indus River in Pakistan. It is a significant project aimed at water storage, power generation, and flood control.

- Option 2: Jhelum

- The Jhelum River does not host the Diamer Basha Dam. It is primarily known for its importance to Kashmir and its contribution to the river system flowing into Pakistan.

- Option 3: Sutlej

- The Sutlej River is another major river in the region, but it is not associated with the Diamer Basha Dam project. It flows from the Himalayas into Pakistan but through different states like Punjab.

- Option 4: Chenab

- The Chenab River is also a significant river in Pakistan's river system, though it is not the site of the Diamer Basha Dam. It flows through Punjab and is part of the larger Indus River system.