Explanation:

- The Allahabad Prasasti, also known as the Allahabad Pillar Inscription, is attributed to Samudra Gupta.

- This inscription describes Samudra Gupta's military conquests and achievements.

- Ashoka (Option 1) is known for his own set of edicts on rock and pillar inscriptions, not the Allahabad Prasasti.

- Harsha (Option 2) ruled later and does not have a connection to this specific inscription.

- Chandra Gupta Maurya (Option 4) was an earlier ruler and is not associated with the Allahabad Prasasti.

Option 3: Samudra Gupta is the correct answer.