In the Lok Sabha, also called the House of the People, the number of representatives allocated to each Indian state is primarily determined on the basis of which of the following factors?

Introduction / Context:
The Lok Sabha is meant to represent the people of India on the basis of population, so the allocation of seats to each state must follow a rational principle. This question asks you to identify the primary factor used to determine how many Lok Sabha constituencies, and therefore members, are allotted to each state. Understanding this principle is important for grasping how representative democracy works in India and how population is linked to political representation.

Given Data / Assumptions:

• The subject is the allocation of Lok Sabha seats among the states.
• The options list area, population, literacy rate and contribution to national income as possible factors.
• We assume a basic knowledge that Lok Sabha members represent roughly equal sized segments of the population.
• We are focusing on the primary constitutional criterion, not on temporary freezes on readjustment.

Concept / Approach:
The Constitution of India provides that the allocation of seats in the Lok Sabha to the states shall be such that the ratio between the number of seats and the population, so far as practicable, is the same for all states. This clearly shows that population is the key factor. Literacy rate, area and contribution to national income may affect development planning, but they are not the legal basis for allotting seats in the Lok Sabha. Therefore, to answer the question, we identify population as the correct determinant and select the option that mentions the census based population of the state.

Step-by-Step Solution:
Step 1: Recall that the Lok Sabha is designed to be a directly elected house representing the people of India. Step 2: The Constitution states that representation should, as far as possible, be proportionate to population. Step 3: Examine option B, which specifically mentions the population of the state as determined by the census, matching the constitutional principle. Step 4: Consider option A, which refers to the geographical area of the state. Area does not necessarily correlate with population density and is not the basis for Lok Sabha seats. Step 5: Consider option C, literacy rate, which might be relevant for social policy but is not used to allocate parliamentary seats. Step 6: Consider option D, contribution to national income, which is an economic measure and again not part of the constitutional criterion for seat distribution. Step 7: Conclude that option B correctly identifies population as the deciding factor.

Verification / Alternative check:
To verify, think about why some states like Uttar Pradesh have many Lok Sabha seats, while smaller states like Goa have very few. Uttar Pradesh has a large population, so it receives a higher number of constituencies to ensure that each Member of Parliament represents a comparable number of people. This logic does not relate directly to area or wealth. Also, when delimitation exercises are discussed, they always refer to census data and population changes, further confirming that population is the deciding factor. This real world observation supports the conclusion that the number of representatives is based on population as recorded in the census.

Why Other Options Are Wrong:
Option A: Geographical area is important for administration and infrastructure, but large areas can be sparsely populated, so it is not the basis for representation in the Lok Sabha.

Option C: Literacy rate is a developmental indicator and can be high or low independent of population size, so it does not determine how many seats a state receives.

Option D: Contribution to national income would favour economically richer states and is not used as a democratic principle for allocating seats in a popular house.

Common Pitfalls:
A common error is to think that area or economic contribution should matter and then to project that idea onto the constitutional design. However, democratic representation focuses primarily on population, so that each citizen has roughly equal voting power in choosing representatives. Another pitfall is to forget that although there is currently a freeze on the readjustment of seats based on newer census figures, the underlying principle remains population. Keeping this distinction clear will help you answer questions on representation and delimitation with confidence.

Final Answer:
The population of the state as determined by the census.