Final answer:
Mary Wilson of The Supremes stated that the girl group received thorough Artist Development training from Motown, helping them to become a successful and polished act.
Step-by-step explanation:
According to Supreme's vocalist Mary Wilson, the girl group received a remarkable wealth of experience and exposure from Motown Records. The label provided them with a platform to showcase their musical talents, as well as rigorous training in performance, etiquette, and style, often referred to as Artist Development.
This intensive grooming helped shape The Supremes into one of the most iconic and successful girl groups of the 1960s, ensuring they maintained a polished and professional image that appealed to both black and white audiences.