Choose appropriate articles for the given sentence: ______ Brahmaputra river, Assam's lifeline has turned muddy and its water has changed colour which is ______ cause for alarm.

The correct answer is ' The, a '. Key Points In English, there are three article s: a, an, and the . Articles are used before nouns or noun equivalents and are a type of adjective. The definite article (the) is used before a noun to indicate that the identity of the noun is known to the reader. The indefinite article (a, an) is used before a noun that is general or when its identity is not known. There are certain situations in which a noun takes no article which are as follows: When non-count nouns are used that refer to items that are not counted and are always singular then no article is used before them. No article is used when we are talking about things in a general way not in a specific way . By referring to the above explanation, it can be concluded that The, a should be the appropriate option to be chosen for filling the blank. Hence, the correct answer is option 3 .