The correct answer is option 4, Ravi.

The site of Harappa, one of the major cities of the Indus Valley Civilization, is located on the bank of the Ravi River. The Indus Valley Civilization was a Bronze Age civilization that flourished in the northwestern part of the Indian subcontinent and is known for its advanced urban planning, sophisticated drainage systems, and well-organized cities.

Option 1, Saraswati, is not the correct answer. The Saraswati River is mentioned in ancient Hindu texts but its exact location and existence in the physical world are still debated among scholars.

Option 2, Indus, is not the correct answer for the specific location of Harappa. Although Harappa is a part of the Indus Valley Civilization, it is specifically situated on the bank of the Ravi River, not the Indus River.

Option 3, Beas, is also not the correct answer. The Beas River is not located in close proximity to the site of Harappa.

Therefore, the correct answer is option 4, Ravi.