I challenged myself to finish my homework within _____________ hour so that I could go out to play with my friends​. A)a B)an C)the D)no article

To determine the correct answer to the sentence, we need to consider the context and grammatical rules regarding articles in English.

Analysis of Options

1. A) a: This article is used before singular nouns that begin with a consonant sound. It indicates one of many.

2. B) an: This article is used before singular nouns that begin with a vowel sound. It suggests one of many in an indefinite way.

3. C) the: This definite article is used when referring to a specific noun known to the reader or listener.

4. D) no article: This is used when no article is needed or when speaking generally about something.

Contextual Usage

In the sentence "I challenged myself to finish my homework within _____________ hour so that I could go out to play with my friends​," we are referring to a non-specific hour.

Conclusion

In this case, the appropriate choice would be A) a, as it signifies "one hour" in a general sense and aligns with the usage of 'hour' starting with a consonant sound.

Final Answer

The correct answer is A) a.