What is the name of classical violin song in Hills Season 3 Episode 19 - Paris Changes Everything when Whitney and Lauren are at Debutante ball?

The classical violin song playing in Hills Season 3 Episode 19, "Paris Changes Everything," when Whitney and Lauren are at the Debutante ball is "Adagio in G Minor" by Remo Giazotto, which is actually a famous arrangement of "Largo" from Albinoni's "Concerto in G Minor".

This piece is commonly referred to as "Albinoni's Adagio," although it's not his original composition. Giazotto created this arrangement in the 1950s, drawing inspiration from a fragment of the original Albinoni score.

It's a beautiful and melancholic piece that fits the emotional tone of the scene in The Hills.