With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: In 2012, Swedish folk duo First Aid Kit released the single "Emmylou" from the album "The Lion's Roar". The song's chorus is a lyrical acknowledgment of the Gram Parsons and Emmylou Harris singing partnership, and to the romantic relationship between them that lacked time to fully develop before his death.
text_B: Is there a mournful aspect to the song Emmylou by First Aid Kit?
YES.