The conquest of Vallabhi by King Harshavardhana is mentioned in which one of the following inscriptions?

Introduction / Context:
In early medieval Indian history, inscriptions are crucial sources for reconstructing political events, conquests, and dynastic relations. Harshavardhana, also known as Harsha, was an important ruler of North India in the seventh century. The question asks about the specific inscription that mentions his conquest of Vallabhi, a significant region in western India. Knowing which inscription records this conquest helps candidates link literary narratives with epigraphic evidence, an important skill in history based examinations.

Given Data / Assumptions:

• We are dealing with the period of Harshavardhana in early medieval India.
• The focus is on his conquest or campaign against Vallabhi.
• Four inscriptions are listed: Aihole Pillar, Junagadh, Navsari Copperplate, and Damodarpur Copperplate.
• Standard historical scholarship on these inscriptions is assumed.

Concept / Approach:
Each listed inscription belongs to a different dynasty or context. The Aihole Pillar Inscription is associated with the Chalukya ruler Pulakeshin II and celebrates his victories, including confrontations with Harsha. The Junagadh Inscription is famous for the records of Rudradaman and later rulers in the Kathiawar region, not specifically Harsha's Vallabhi conquest. The Damodarpur copper plates relate to the Gupta administration in Bengal. The Navsari Copperplate Inscription, however, provides information about events in western India and is associated with the Chalukyas and their interactions with Harsha and Vallabhi. It is this Navsari Copperplate Inscription that refers to the Vallabhi campaign of Harshavardhana.

Step-by-Step Solution:

Verification / Alternative check:
A broader way to check is to group inscriptions by region and ruling power. Vallabhi and the events involving Harsha and western Indian powers are more likely recorded in inscriptions from the western region, such as Navsari. The Aihole and Junagadh inscriptions have well known standard content that most history students learn separately, and they do not focus on the Vallabhi conquest by Harsha. This cross checking confirms that Navsari Copperplate Inscription is the accurate choice.

Why Other Options Are Wrong:

• Aihole Pillar Inscription: Primarily celebrates the Chalukya ruler Pulakeshin II and his campaigns; it mentions Harsha as a rival but does not describe Harsha conquering Vallabhi.
• Junagadh Inscription: Famous for Rudradaman's achievements and later records in Kathiawar, not specifically for Harshavardhana's Vallabhi conquest.
• Damodarpur Copperplate Inscription: Connected with Gupta administration in eastern India, especially Bengal, and does not deal with Vallabhi under Harsha.

Common Pitfalls:
Students sometimes select the Aihole Inscription simply because it is strongly associated with Harsha as an opponent of Pulakeshin II, without noticing the specific requirement about Vallabhi. Another common error is to choose Junagadh due to its western Indian location, even though the content focus is different. Mixing inscriptions by geography instead of by content can lead to confusion. The safer strategy is to link each inscription with its main ruler and key events before answering.

Final Answer:
The conquest of Vallabhi by King Harshavardhana is mentioned in the Navsari Copperplate Inscription.