A popular pilgrimage destination in Tamil Nadu is:

Velankanni
Rameshwaram
Tirupati
Haridwar

The correct answer is Tirupati.

Tirupati is a city in the Indian state of Andhra Pradesh. It is one of the most popular pilgrimage destinations in India, and is home to the Venkateswara Temple, a Hindu temple dedicated to the god Vishnu. The temple is one of the richest temples in the world, and is visited by millions of pilgrims every year.

Velankanni is a town in the Indian state of Tamil Nadu. It is a popular pilgrimage destination for Catholics, and is home to the Shrine of Our Lady of Good Health, a Marian shrine. The shrine is one of the most popular pilgrimage destinations in India, and is visited by millions of pilgrims every year.

Rameshwaram is a town in the Indian state of Tamil Nadu. It is a popular pilgrimage destination for Hindus, and is home to the Ramanathaswamy Temple, a Hindu temple dedicated to the god Shiva. The temple is one of the most important temples in Hinduism, and is visited by millions of pilgrims every year.

Haridwar is a city in the Indian state of Uttarakhand. It is a popular pilgrimage destination for Hindus, and is home to the Haridwar Ghat, a series of ghats (steps leading down to the river) on the banks of the Ganges River. The ghats are a popular spot for bathing and religious ceremonies, and are visited by millions of pilgrims every year.