In early Buddhist history, the Third Buddhist Council was convened and held at which important imperial city of the Mauryan period?

Introduction / Context:
The Buddhist councils were important meetings of monks that tried to settle doctrinal issues and preserve the teachings after the passing of the Buddha. Questions about these councils often ask you to match each council with its place and patron. The Third Buddhist Council is especially famous because it is connected with Emperor Ashoka and a major effort to purify and spread the Buddhist Sangha.

Given Data / Assumptions:

• The question is about the Third Buddhist Council, not the first or second.
• We are looking for the city where it was held.
• Options include several ancient cities from different regions of India.

Concept / Approach:
Traditional accounts state that the First Council was held at Rajgir shortly after the Buddha death, the Second at Vaishali, and the Third at Pataliputra during the reign of Ashoka. Pataliputra was the Mauryan capital and a major centre of political and religious activity. It makes sense historically that a council concerned with discipline and missionary work would be held under imperial patronage in this capital city.

Step-by-Step Solution:
Step 1: Recall the standard list of councils: first at Rajgir, second at Vaishali and third at Pataliputra. Step 2: Associate the Third Council with Ashoka, who ruled from Pataliputra. Step 3: Examine the options and locate Pataliputra among them. Step 4: Confirm that other cities such as Vatsa or Kashmir are not traditionally connected with the Third Council. Step 5: Select option B, Pataliputra, as the correct place for the Third Buddhist Council.

Verification / Alternative check:
As a quick verification, think of how exam guides often present a simple table: Rajgir equals first council, Vaishali equals second, Pataliputra equals third and sometimes Kashmir or other places for later councils. Whenever you see the number three together with Ashoka, Pataliputra should come to mind as the imperial capital that hosted this meeting.

Why Other Options Are Wrong:
Option A, Vatsa, is the name of a mahajanapada or region but is not the seat of the Third Council. Option C, Kosambi, was an important city but again not the chosen venue for this particular council. Option D, Kashmir, is associated in some traditions with a later council under Kanishka, not the Third Council. Option E, Ujjain, was another major city but has no standard link with the Third Buddhist Council in exam oriented history.

Common Pitfalls:
Students often confuse the councils and randomly pair city names with council numbers. Another pitfall is to pick a city that simply sounds important without recalling the specific association taught in textbooks. To avoid errors, memorise a fixed sequence of councils and their locations and always link the number three with Pataliputra and Ashoka.

Final Answer:
The Third Buddhist Council was held at Pataliputra, the imperial capital of the Mauryan empire.