Final answer:
Jon Hendricks was best known for his contributions to jazz as a singer and lyricist, particularly in the art of vocalese. He was renowned for writing and performing lyrics to instrumental jazz standards, leaving a lasting impact on jazz vocal techniques.
Step-by-step explanation:
Jon Hendricks was best known for A) Jazz singing. A master of vocal jazz and a pioneer of the art of vocalese, Hendricks was celebrated for his ability to write and perform lyrics to existing instrumental songs, particularly jazz standards. His innovative work has influenced generations of jazz vocalists. Hendricks' style showcased his proficiency with rhythm, rhyme, and his ability to mimic instrumental sounds, which allowed his voice to seamlessly blend with other instruments in a jazz ensemble. His contributions to jazz were not only as a singer but also as a lyricist, bringing a new dimension to jazz compositions. He was a performer who truly understood the intricacies of bebop and could translate instrumental improvisation into scintillating vocal expression.