I had no clue, so I gave the task to an AI
assistant (GPT-4).
Answer:
Based on the description and the provided melody,
it seems
that you are referring to the Serenade for Strings in C Major,
Op. 48, specifically the second movement "Waltz" by Pyotr
Ilyich Tchaikovsky. The Waltz is indeed written in 3/4 time,
and it is a well-known and beloved piece from the Romantic
period. The Serenade for Strings as a whole is a popular
work in the classical repertoire, often performed by string orchestras.
Is it the correct guess or just some AI hallucination?
It's wrong, and apparently based on the textual description only.
The melody is totally unrelated.