Which of the following leaders became the Prime Minister of Nepal in 2015 after the adoption of the country's new Constitution?

Introduction / Context:
Nepal has undergone significant political changes in recent decades, including the end of monarchy, the drafting of a new Constitution, and the formation of new governments. Competitive exams often ask about key political leaders who headed the government during these turning points. This question focuses on identifying the leader who became Prime Minister of Nepal in 2015 after the promulgation of the new Constitution, a fact that appears frequently in contemporary affairs sections.

Given Data / Assumptions:

• The event in focus is the adoption of a new Constitution by Nepal in 2015.
• The question asks who became Prime Minister of Nepal following that event.
• Options include Keshav Kumar Budhathoki, Khadga Prasad Sharma Koli, Sushil Koirala, Pushpakamal Dahal 'Prachanda', and Baburam Bhattarai.
• The spelling Khadga Prasad Sharma Koli refers to Khadga Prasad Sharma Oli, commonly written as K P Sharma Oli.

Concept / Approach:
After years of political transition, Nepal adopted its new Constitution in September 2015. Shortly thereafter, Khadga Prasad Sharma Oli, widely known as K P Sharma Oli, was elected as Prime Minister. Sushil Koirala had been Prime Minister before the Constitution was finalised, while Pushpakamal Dahal 'Prachanda' and Baburam Bhattarai served as Prime Ministers in other periods. Therefore, the correct approach is to connect the specific year 2015 and the constitutional milestone with K P Sharma Oli, represented here as Khadga Prasad Sharma Koli.

Step-by-Step Solution:
Step 1: Note the time marker in the question: the year 2015 and the adoption of a new Constitution. Step 2: Recall that K P Sharma Oli became Prime Minister of Nepal in October 2015, shortly after the new Constitution came into force. Step 3: Identify that Khadga Prasad Sharma Koli in the options refers to this leader despite the minor spelling variation. Step 4: Remember that Sushil Koirala served immediately before Oli, and Prachanda and Baburam Bhattarai held the office in earlier or later phases, not specifically tied to the 2015 Constitution event. Step 5: Select Khadga Prasad Sharma Koli as the correct answer since he matches both the name and the timing described.

Verification / Alternative check:
You can verify this by scanning lists of recent Prime Ministers of Nepal in current affairs yearbooks, which show Sushil Koirala up to 2015 and K P Sharma Oli taking over after the new Constitution was adopted. News summaries that review the constitutional process often mention Oli election as a key political development following the new charter. The other leaders in the options appear in different years and contexts, confirming that only Khadga Prasad Sharma Koli (K P Sharma Oli) fits the specific clue in the question.

Why Other Options Are Wrong:
Keshav Kumar Budhathoki is not widely recognised in exam level lists of Nepal Prime Ministers, so this choice is incorrect. Sushil Koirala was Prime Minister before the Constitution was finalised, which means he does not match the after adoption condition. Pushpakamal Dahal 'Prachanda' served as Prime Minister on more than one occasion, but his most recent term began in 2016, not in 2015 immediately after the new Constitution. Baburam Bhattarai, another Maoist leader, held the office earlier and resigned well before 2015. Thus, these names do not satisfy the timing requirement given in the question.

Common Pitfalls:
A common pitfall is to pick Sushil Koirala simply because he is a familiar name or because candidates remember he was Prime Minister around the period of constitutional debates. Another mistake is to be confused by the slightly altered spelling of Oli name in the option and to hesitate in choosing it. To avoid these issues, focus on anchoring each leader to a specific political milestone or year: Sushil Koirala with pre Constitution coalition politics, K P Sharma Oli with the immediate post Constitution government in 2015, and Prachanda with later coalition arrangements. Such chronological anchoring helps you answer similar questions more confidently.

Final Answer:
The leader who became Prime Minister of Nepal in 2015 after the adoption of the new Constitution was Khadga Prasad Sharma Koli, that is, K P Sharma Oli.