In 2015, the Planning Commission was replaced with the ___________.

Correct option is D

In 2015, the Planning Commission was replaced with the NITI Aayog. NITI Aayog (National Institution for Transforming India) is a policy think-tank of the Government of India, established on 1st January 2015.
The NITI Aayog comprises the Prime Minister of India as the Chairperson, along with several other Union Ministers, Chief Ministers of all the States, and members from various fields such as economics, agriculture, health, education, and social welfare.
The Vice-Chairperson, CEO, and full-time members of the NITI Aayog are appointed by the Prime Minister.
B.V.R Subramaniyam is the current and 4th CEO of NITI Aayog and Suman Bery is the newly appointed Vice Chairman of NITI Aayog.