Question

Fill in the blank with the appropriate article:

Copper is _____ useful metal.

• A. an
• B. no article
• C. the
• D. a

Answer 1

Answer: (D)

1. An/A' is used as an indefinite article for a thing or person when the reader doesn't know which one we are referring to out of many nouns. It states the random nature of the subject.
   
2. 'The' is used as a definite article for a thing or person when the reader knows which one we are exactly referring to. It states the specific nature of the subject.

Option A is incorrect as 'An' is used as an indefinite article with a word having a vowel sound, although in this sentence 'Useful' begins with 'U' ,a vowel but it has a consonant sound. Option B is incorrect as 'The ' is used for a particular noun out of many nouns. Option C is incorrect grammatically. incorrect . In Option D 'a' is used as the indefinite article with a singular countable noun and is grammatically correct.