A pillar containing inscriptions from three different periods, i.e. the Mauryan period, Gupta period and Mughal period, is located at:

Allahabad (Prayagraj)

The correct answer is Option 3- Allahabad (Prayagraj)

The pillar containing inscriptions from three different periods, i.e. the Mauryan period, Gupta period and Mughal period, is located at Allahabad (Prayagraj).

It is known as the Allahabad Pillar, also known as the Prayag Prasasti or Ashoka Stambha. It is a 10.65 meters (35 feet) high monolith pillar erected by Ashoka the Great, the 3rd Maurya emperor who reigned over much of South Asia from c. 268 to 232 BCE. The pillar contains edicts issued by Ashoka, as well as later inscriptions from the Gupta period and the Mughal period.

The Ashokan inscriptions on the pillar are among the earliest known examples of written Sanskrit. They contain a variety of information, including Ashoka's moral and religious teachings, his policies on social welfare and government, and his accounts of his military campaigns.

The Gupta inscriptions on the pillar date from the 4th century CE. They are written in Sanskrit and Prakrit and record the military conquests of Samudragupta, the second Gupta emperor.

The Mughal inscription on the pillar dates from the 17th century CE. It is written in Persian and records the visit of the Mughal emperor Jahangir to Allahabad in 1619.

The Allahabad Pillar is a unique and important historical monument. It is one of the few surviving Ashoka pillars and it is the only known pillar that contains inscriptions from three different periods. It is a testament to the rich and diverse cultural heritage of India.