According to Article 1 of the Constitution of India, the country is described by which of the following expressions?

Introduction / Context:
Article 1 of the Constitution gives the official description of India in constitutional terms. This simple but important statement reflects the nature of the Indian Union and has implications for how federalism is understood. Many exam questions ask you to recall the exact phrase used in Article 1 because it captures the idea that India is a union with an indestructible unity even though it has states with their own governments.

Given Data / Assumptions:

The question refers specifically to Article 1 of the Constitution.

It asks which expression is used to describe India as a state.

Options provide different possible characterisations such as federal state, unitary state and union of states.

Concept / Approach:
Article 1 states that India, that is Bharat, shall be a Union of States. The framers intentionally used the term Union rather than Federation. This choice emphasises that the Indian Union is not a result of an agreement among sovereign states and that the states have no right to secede. Although in practice India has many features of a federation, the constitutional text avoids the term federal state in Article 1 and instead uses Union of States as the formal description.

Step-by-Step Solution:
Step 1: Recall the exact wording of Article 1, which begins India, that is Bharat, shall be a Union of States. Step 2: Note that the words federal state or unitary state do not appear in Article 1. Step 3: The idea of quasi federal is an academic description used by scholars, not the wording of Article 1. Step 4: Therefore, the only option that matches the constitutional text is Union of States.

Verification / Alternative check:
You can verify this by remembering how standard polity texts quote Article 1. The sentence India, that is Bharat, shall be a Union of States is often printed in full. If you mentally recite this sentence, you can immediately see that Union of States is the key descriptive phrase. The other terms in the options are analytic labels that political scientists use but are not part of the official constitutional wording.

Why Other Options Are Wrong:
Federal State: India is often described as a federal system with a strong centre, but Article 1 does not use the words federal state anywhere.
Quasi Federal State: This term is used by scholars to highlight that India combines federal and unitary features. It is not an expression used in Article 1.
Unitary State: India is not a strictly unitary state, because power is constitutionally divided between the Union and the states. Article 1 does not describe India in this way.

Common Pitfalls:
A common mistake is to answer based on descriptive labels rather than the exact constitutional text. Examiners often test whether candidates can distinguish between what the Constitution actually says and how scholars describe it in books. To avoid this, whenever a question mentions a specific article, focus on the precise words used in the article. For Article 1, always remember the phrase Union of States paired with India, that is Bharat.

Final Answer:
Article 1 of the Constitution of India describes the country as a Union of States.