The Delimitation Commission is responsible for the redrawing of constituency boundaries in India to ensure fair representation of the population. The process of delimitation aims to allocate seats in a manner that reflects the demographic changes and ensures equal representation for all citizens. Among the options given, the correct answer is option 'A', which states that the Delimitation Commission ensures fair representation by increasing the number of constituencies in densely populated areas.

Here is a detailed explanation of how increasing the number of constituencies in densely populated areas helps to ensure fair representation of the population:

1. Equal representation: By increasing the number of constituencies in densely populated areas, the Delimitation Commission ensures that each constituency represents an approximately equal number of people. This is important for upholding the principle of one person, one vote, and prevents the dilution of voting power in densely populated regions.

2. Balancing demographic changes: Over time, population distribution within a country can change due to various factors such as migration, urbanization, and demographic shifts. By increasing the number of constituencies in densely populated areas, the Delimitation Commission can reflect these changes and ensure that each constituency represents the current population accurately.

3. Avoiding overcrowding: Densely populated areas often have a higher number of eligible voters. If the number of constituencies remains fixed while the population increases, there would be overcrowding of voters in each constituency. By increasing the number of constituencies, the Delimitation Commission can distribute the voters more evenly, reducing overcrowding and facilitating better representation.

4. Enhanced political participation: Increasing the number of constituencies in densely populated areas can also increase political participation. With more local representatives available, citizens residing in densely populated areas have a better chance of being represented by someone who understands their specific concerns and can effectively address them.

5. Effective governance: By ensuring fair representation through increased constituencies, the Delimitation Commission helps to create a more responsive and accountable political system. With a better representation of the population, policymakers can make well-informed decisions that reflect the needs and aspirations of the people they represent.

In conclusion, increasing the number of constituencies in densely populated areas is a crucial step taken by the Delimitation Commission to ensure fair representation of the population. It helps to maintain the principle of equal representation, balance demographic changes, prevent overcrowding, enhance political participation, and promote effective governance.