Final answer:
Ella Fitzgerald is the acclaimed female jazz singer known for her outstanding scat singing, a technique so influential that it's been studied by instrumentalists. Unlike Bessie Smith, who was known for Blues and powerful vocal performances, Fitzgerald's scat singing set her apart in jazz history.
Step-by-step explanation:
The female jazz singer who is considered one of the greatest scat singers in all of jazz and whose technique has been studied by instrumentalists is B) Ella Fitzgerald. While Dinah Washington, Ethel Waters, and Billie Holiday were all exceptional singers with their own styles and influences, Ella Fitzgerald is renowned for her scat singing, an improvisational technique that mimics instrumental solos using the voice. Ella's scatting ability was indeed so extraordinary that even instrumentalists have studied her technique to improve their own improvisational skills.
In contrast, Blues music, resonant with the experiences of African-Americans, found a powerful voice in Bessie Smith, known as "The Empress of the Blues." Though not a scat singer, her emotionally potent performances and collaborations, particularly with Louis Armstrong on works like Saint Louis Blues, and her memorable songs such as Nobody Knows You When You're Down and Out, left a lasting impact on the genre.