Who among the following was appointed chairman of the Indian Space Research Organisation (ISRO) in January 2018, succeeding A. S. Kiran Kumar?

Introduction / Context:
The chairman of the Indian Space Research Organisation leads India civil space programme and is responsible for major missions, launch vehicle development, and satellite projects. Changes in this position are important news events. In January 2018, a new chairman took over from A. S. Kiran Kumar. This question asks you to identify that successor from the list of names provided.

Given Data / Assumptions:
- The focus is on the chairman of ISRO appointed in January 2018.
- A. S. Kiran Kumar was the outgoing chairman at that time.
- The options are M. Y. S. Prasad, Kailasavadivoo Sivan, A. S. Kiran Kumar, and K. Radhakrishnan.
- We assume awareness of recent ISRO leadership and major missions.

Concept / Approach:
Kailasavadivoo Sivan, often called K. Sivan, is a well known rocket scientist associated with the PSLV and GSLV programmes. He was appointed chairman of ISRO in January 2018, succeeding A. S. Kiran Kumar. Earlier, K. Radhakrishnan had served as chairman before A. S. Kiran Kumar. Knowing this sequence of leadership allows us to identify Kailasavadivoo Sivan as the correct answer.

Step-by-Step Solution:
Step 1: Recall the line of recent ISRO chairmen: K. Radhakrishnan, then A. S. Kiran Kumar, followed by K. Sivan. Step 2: Note that the question asks for the person appointed in January 2018, just after A. S. Kiran Kumar term. Step 3: Recognise that this appointment was of Kailasavadivoo Sivan, who had previously led the Vikram Sarabhai Space Centre and worked on launch vehicles. Step 4: Compare this knowledge with the answer choices provided. Step 5: Select Kailasavadivoo Sivan as the correct option.

Verification / Alternative Check:
News articles and ISRO announcements from early 2018 prominently mention K. Sivan taking charge as chairman. They highlight his background with the PSLV and GSLV Mk III programmes. In contrast, K. Radhakrishnan tenure ended earlier, and A. S. Kiran Kumar is the person being succeeded in this question. M. Y. S. Prasad is associated with other leadership roles in Indian space institutions but not as chairman in 2018. This confirms the answer.

Why Other Options Are Wrong:
M. Y. S. Prasad: A senior space scientist but not the person appointed as chairman of ISRO in January 2018.
A. S. Kiran Kumar: He was the outgoing chairman, not the new appointee mentioned in the question.
K. Radhakrishnan: Served as chairman earlier, before A. S. Kiran Kumar, and so does not fit the 2018 succession described here.

Common Pitfalls:
Students sometimes confuse the order of ISRO chairmen and may pick K. Radhakrishnan because he is widely known. Another mistake is to overlook the phrase succeeding A. S. Kiran Kumar, which clearly signals that we are talking about the next person in line. Keeping a clear timeline of key science leaders helps avoid such errors.

Final Answer:
The scientist appointed as chairman of ISRO in January 2018, after A. S. Kiran Kumar, was Kailasavadivoo Sivan.