The correct answer for the question is option 2, KN Raj.

To understand why KN Raj is the correct answer, let`s take a look at the options and examine their roles in the First Five Year Plan.

Option 1, P C Mahalanobis, was indeed involved in the planning process of the First Five Year Plan but he did not draft the entire plan himself. Mahalanobis was an Indian economist and statistician who played a significant role in formulating the plan by introducing the concept of a "growth-oriented" plan based on the use of statistical data and analysis.

Option 3, J C Kumarappa, was an Indian economist and disciple of Mahatma Gandhi. He was primarily involved in the field of agricultural planning but he did not draft the First Five Year Plan.

Option 4, Jawaharlal Nehru, was the first Prime Minister of India and a key figure in the planning and implementation of the First Five Year Plan. However, he did not personally draft the plan.

Therefore, option 2, KN Raj, is the correct answer as he was one of the main architects who drafted the First Five Year Plan. KN Raj was an Indian economist and member of the Planning Commission of India, which was responsible for formulating