Explanation

The Kothari Commission (the National Education Commission, 1964–66), chaired by D. S. Kothari, was appointed by the Government of India in July 1964 to advise on a national pattern of education at all stages. Its report, submitted in 1966, recommended the 10+2+3 structure and the target of spending 6% of GNP on education, forming the basis of the National Policy on Education, 1968. The year 1966 marks the report's submission, not the Commission's appointment; 1965 and 1967 are incorrect. Hence option D (1964).