- 'Phase-I' of population growth in India is characterized by a stagnant phase of population growth, where the birth rate and death rate are both high, leading to a low or negative net growth of population (Option II).
- The rapid fall in the mortality rate (Option III) is a characteristic of later stages of population growth, not of Phase-I. Hence, it is incorrect for Phase-I.
- Poor health and medical services (Option IV) contributed to the stagnation of population growth in Phase-I as India faced significant challenges in healthcare and infrastructure during this phase.
Thus, the correct answer is (C) Only I, II and IV are correct.