The correct answer is: D. no article
The sentence “I want flowers in your garden” is a general statement about flowers, not a specific request for a particular type of flower. Therefore, we do not need to use an article.
The article “a” is used before singular nouns that refer to a general class of things. For example, “I want a flower” could mean “I want any flower,” or “I want a particular type of flower.”
The article “an” is used before singular nouns that begin with a vowel sound. For example, “I want an apple” could mean “I want any apple,” or “I want a particular type of apple.”
The article “the” is used before singular nouns that refer to a specific thing or person. For example, “I want the flower that you gave me” could mean “I want the flower that you gave me yesterday,” or “I want the flower that you gave me last week.”
In the sentence “I want flowers in your garden,” we are not referring to a specific type of flower, so we do not need to use an article.