The correct option is C Establishment of schools, colleges, and universities
The literacy rate is defined by the percentage of the population of a given age group that can read and write.
Post independence, India's education system was in a dire state and hence, the Five-Year Plans aimed at improving this. Several reforms in education have helped establish schools, colleges, and universities in India. This increased the number of students enrolled in schools and colleges. Hence, the literacy rate improved from 18.33% in 1951 to 77.7% in 2017.