Explanation:

- Harappa:

Harappa is indeed a city of the Indus Valley Civilization, which was one of the world's earliest urban societies, flourishing around 2500 BCE. Located in present-day Pakistan, it is one of the major archaeological sites providing evidence of this advanced ancient society.

- Sanchi:

Sanchi is famous for its Buddhist stupas and is located in Madhya Pradesh, India. It did not exist during the Indus Valley Civilization, as it became prominent much later, particularly in the Mauryan Empire times.

- Muziris:

Muziris was an ancient port city on the Malabar Coast of India, known in the Greco-Roman world. Its existence postdates the Indus Valley Civilization, being more relevant in the first millennium CE.

- Ayodhya:

Ayodhya is an ancient city in India, known in various historical and religious texts, especially in Hindu epics like Ramayana. However, it is associated more with later periods and not with the Indus Valley Civilization.