Explanation: In English grammar, articles are used to indicate the definiteness or indefiniteness of a noun. There are two types of articles: definite and indefinite. The definite article is "the," and the indefinite articles are "a" and "an."
When using superlative adjectives, which indicate the highest degree of a quality (e.g., "most beautiful," "tallest," "smartest"), the definite article "the" is used. This is because superlatives refer to a specific quality or characteristic that is unique among a group. For example, "the most beautiful city" implies that Mysore is uniquely beautiful among all the cities in Karnataka.
The use of "the" before a superlative adjective is a grammatical rule that helps to specify the exact quality being referred to. It is important to note that "a" and "an" are not used before superlatives because they do not indicate a specific quality. Instead, "a" and "an" are used before singular nouns to indicate that the noun is not a specific, known entity.
In the given sentence, "Mysore is the most beautiful city in Karnataka," the use of "the" is correct because it specifies that Mysore is uniquely beautiful among the cities in Karnataka. The other options, "an" and "a," would be incorrect because they do not convey the specific quality that "the" does. The option "un" is not a valid article in English and is therefore incorrect.
Understanding the use of articles with superlative adjectives is crucial for correct English grammar, especially in contexts where precision and specificity are important, such as in competitive examinations and formal writing.