Explanations:In English grammar, articles are used to indicate whether a noun is specific or general. There are two types of articles: definite and indefinite. The definite article "The" is used to refer to a specific or particular member of a group, while indefinite articles "A" and "An" are used to refer to any non-specific member of a group.
When referring to unique entities such as countries, rivers, and capital cities, the definite article "The" is typically used. This is because these entities are specific and singular in their context. For example, "The United States," "The Amazon River," and "The capital of India" all use "The" to indicate the specific entity being referred to.
In the given sentence, "Piyush lives in Delhi, ..... capital of India," the correct article to use is "The" because Delhi is the specific and unique capital of India. The sentence is referring to a particular and specific entity, and thus requires the definite article "The" to convey this specificity.
Using "A" or "An" would be incorrect because these indefinite articles suggest a non-specific entity, which does not apply to the capital of a country. Similarly, leaving out the article entirely would be grammatically incorrect in this context, as the sentence requires a definite article to specify the unique entity.
Understanding the use of articles in specific contexts is crucial for proper English grammar and clear communication. The definite article "The" is used to indicate a specific and unique entity, which is why it is the correct choice in this sentence.