The correct answer is A. Mahalanovis model.
The Mahalanobis model was a development planning model developed by Indian economist P. C. Mahalanobis. It was used to formulate the First Five Year Plan of India. The model was based on the idea that economic development could be achieved by increasing the rate of investment in heavy industry. The model also emphasized the need for self-reliance in the Indian economy.
The Feldman model is a development planning model developed by Soviet economist G. A. Feldman. It was based on the idea that economic development could be achieved by increasing the rate of investment in capital goods. The model also emphasized the need for balanced growth in the economy.
The Harrod-Domar model is a development planning model developed by British economist Roy Harrod and American economist Evsey Domar. It was based on the idea that economic development could be achieved by increasing the rate of investment. The model also emphasized the need for savings and capital accumulation.
The Nehan-Mahalanovis model is a development planning model developed by Indian economist V. K. Nehan and P. C. Mahalanobis. It was based on the idea that economic development could be achieved by increasing the rate of investment in both heavy industry and light industry. The model also emphasized the need for self-reliance in the Indian economy.