Who was the Chief Election Commissioner of India in the year 2018?

Introduction / Context:
This question belongs to the current affairs and polity category and focuses on the leadership of the Election Commission of India. The Chief Election Commissioner heads the body that conducts free and fair elections in the country. Knowing who occupied this post in a particular year is important for examinations that test knowledge of constitutional authorities and recent appointments.

Given Data / Assumptions:

• The year of interest is 2018.
• Four prominent names are listed, some of whom have served in different high level roles.
• Only one person was officially designated as the Chief Election Commissioner in 2018 for the major part of that year.

Concept / Approach:
The appointment of the Chief Election Commissioner is notified by the Government of India and widely reported in the media. Om Prakash Rawat, a former civil servant and Election Commissioner, took over as Chief Election Commissioner in January 2018. Sunil Arora joined later and succeeded him towards the end of 2018. For most exam questions that simply ask for the Chief Election Commissioner in 2018, Om Prakash Rawat is taken as the correct response.

Step-by-Step Solution:
Step 1: Identify which of the listed persons have been associated with the Election Commission. Step 2: Recall that Om Prakash Rawat was appointed Chief Election Commissioner in early 2018. Step 3: Note that Ashok Lavasa served as Election Commissioner, not as Chief Election Commissioner during that period. Step 4: Recognise that Montek Singh Ahluwalia was a planning and economic policy expert, not head of the Election Commission. Step 5: Understand that Sunil Arora succeeded Rawat later in the year, but the question context usually points to the main appointment associated with 2018, which is Om Prakash Rawat.

Verification / Alternative check:
Official press releases and newspapers from January 2018 clearly mention the oath taking of Om Prakash Rawat as Chief Election Commissioner. Subsequent news in the same year show Sunil Arora being elevated to that post only towards the end of 2018. Most static GK compilations therefore associate the year 2018 with Om Prakash Rawat for exam purposes, confirming this choice as correct.

Why Other Options Are Wrong:
Ashok Lavasa: Served as an Election Commissioner but was not the Chief Election Commissioner in 2018.
Montek Singh Ahluwalia: An economist and former Deputy Chairperson of the Planning Commission, unrelated to this post.
Sunil Arora: Became Chief Election Commissioner later in 2018, yet exam questions based on the main appointment usually point to Om Prakash Rawat as the answer.

Common Pitfalls:
A common confusion is between Election Commissioners and the Chief Election Commissioner, since similar names appear in news around the same time. Another pitfall is remembering only the latest office holder and ignoring the month of appointment, which can lead to selecting Sunil Arora without considering the context. Reading year wise current affairs carefully helps avoid such mistakes.

Final Answer:
Om Prakash Rawat was the Chief Election Commissioner of India in 2018.