. . . . . . . . water of that river is not fit for drinking. A. a B. an C. the D. no article

The correct answer is D. no article.

The article “a” or “an” is used before singular nouns that refer to a general thing or person. For example, “I saw a bird.” The article “the” is used before singular nouns that refer to a specific thing or person. For example, “I saw the bird that I saw yesterday.”

In the sentence “The water of that river is not fit for drinking,” the noun “water” is a non-count noun. Non-count nouns do not have plural forms and are not preceded by articles.

Here are some other examples of non-count nouns:

• air
• food
• furniture
• homework
• information
• knowledge
• money
• music
• paper
• sand
• sleep
• snow
• sugar
• water
• work

I hope this helps!