Which of the following options adequately describe the year 1921 in Indian context?

Year of the Great Divide.

The correct answer is Option (3) - Year of the Great Divide.

Before 1921 the growth of population was low whereas, after 1921 population rose continuously and rapidly. Thus, 1921 is marked as an Year of the Great Divide which bifurcated the 2 different growth trends in the population.