Explanation:

Sure, let's explore the options:

- Option 1: Harappa

- Harappa is the correct site where the Indus Valley Civilization was first discovered.

- In the 1920s, this ancient city was unearthed in present-day Pakistan.

- Option 2: Rakhigarhi

- Rakhigarhi is another significant Indus Valley site.

- It's one of the largest sites discovered so far.

- However, it was identified much later than Harappa.

- Option 3: Hulas

- Hulas is a site associated with later cultures.

- It is not part of the major Indus Valley discoveries.

- Option 4: Sinauli

- Sinauli is known for having ancient burial sites.

- It is not related to the initial discoveries of the Indus Valley Civilization.

Answer: Harappa