The identification of Lumbini as the birthplace of Gautama Buddha is firmly supported by an ancient pillar inscription left by which Indian ruler?

Introduction / Context:
Several holy sites connected with the life of the Buddha are confirmed not only by Buddhist texts but also by archaeological evidence. Lumbini, in present day Nepal, is recognised as the birthplace of Gautama Buddha. One of the strongest historical pieces of evidence is an ancient inscription on a pillar that records a visit by a famous Indian emperor. This question asks which ruler left that inscription.

Given Data / Assumptions:

• The place is Lumbini, regarded as the birthplace of Buddha.
• The evidence is an inscription on a pillar.
• The options list rulers from different dynasties and periods, including the Mauryan and later times.

Concept / Approach:
Emperor Ashoka of the Maurya dynasty is well known for installing inscribed pillars at various Buddhist sites. One such pillar stands at Lumbini, recording his pilgrimage and acknowledging the place as the birthplace of the Buddha. Later rulers such as Kanishka and Harsha supported Buddhism but the specific Lumbini inscription is clearly linked to Ashoka. Therefore, the correct answer must be the Mauryan emperor who travelled widely and left many rock and pillar edicts.

Step-by-Step Solution:
Step 1: Recall that Ashoka adopted Buddhism and visited important Buddhist holy places. Step 2: Remember that he erected pillars with inscriptions in Brahmi script at sites like Lumbini, Sarnath and others. Step 3: Identify that the pillar at Lumbini specifically states that the Buddha was born there and that Ashoka reduced the village tax. Step 4: Compare the options and note that Pushyamitra Shunga is sometimes remembered as a persecutor rather than a patron of Buddhism, and later kings have different associations. Step 5: Select Ashoka as the ruler whose inscription confirms Lumbini as the Buddha birthplace.

Verification / Alternative check:
To verify, recall a standard exam fact that the Lumbini pillar inscription of Ashoka is direct archaeological proof of the Buddha birthplace. Many textbooks specifically mention this as one of the reasons historians are confident about Lumbini location. None of the other rulers listed in the options are connected so strongly with pillar inscriptions at major Buddhist sites.

Why Other Options Are Wrong:
Option B, Pushyamitra Shunga, came after Ashoka and is not known for such pillar inscriptions. Option C, Kanishka, convened a Buddhist council at Kashmir but did not leave the Lumbini inscription. Option D, Harsha, was a later king who supported Buddhism but again has no direct link to this pillar. Option E, Chandragupta Maurya, founded the Mauryan dynasty but the famous pillar inscriptions belong to his grandson Ashoka rather than to him.

Common Pitfalls:
A common mistake is to confuse different Buddhist patron kings and attribute all achievements to Kanishka or Harsha. Another error is to know that Ashoka installed many pillars but forget exactly which site is connected with which inscription. To avoid confusion, memorise a few key pairings such as Lumbini and Ashoka, Sarnath and Ashokan lion capital, and Pataliputra and Mauryan capital city.

Final Answer:
The Lumbini birthplace of Buddha is attested by a pillar inscription of Ashoka.