Topic: Article,

Best Answer Explained in Below-:

In the sentence "The dress was designed by __ famous Italian artist," the correct choice is "a" (Option A) because it fits the grammatical context of the sentence. The phrase "a famous Italian artist" is used to introduce a non-specific individual from a broader group—any famous Italian artist, rather than a particular one.

The indefinite article "a" is typically used before singular, countable nouns that start with a consonant sound, as is the case here. It suggests that the identity of the artist is not known to the reader and emphasizes that there are many famous Italian artists without specifying which one.

In contrast, "the" (Option B) would imply a specific artist that has already been mentioned or is known to the reader, which doesn't fit since the sentence does not provide any prior context. "An" (Option C) is also incorrect in this case, as it is used before words that begin with a vowel sound, and "famous" begins with a consonant sound. "One" (Option D) would suggest a particular unit among many, which is not the intention of this sentence. Hence, "a" is the most appropriate choice.