Step 1: Understanding the Concept:
The Demographic Transition Theory (DTT) describes the transition of a society from high birth and death rates to low birth and death rates as it develops.
Step 2: Detailed Explanation:
Statement I: This is correct. DTT is a powerful tool for demographers to understand the current stage of a region and forecast its future population growth based on historical development patterns.
Statement II: This is incorrect. In the first stage of demographic transition, both fertility (birth rate) and mortality (death rate) are high. Mortality remains high because of lack of food security, epidemics, and poor sanitation. Medical advancements typically lead to a drop in mortality in the second stage.
Step 3: Final Answer:
Since Statement I is a valid use of the theory and Statement II misidentifies the characteristics of the first stage, option (B) is the correct choice.