Ariana Grande wins Video of the Year following performances by Lady Gaga, Mariah Carey and others
Mariah Carey. (Manny Carabel/Getty Images for MTV) Ahead of receiving this year’s Video Vanguard Award, Mariah Carey serenaded audiences with a medley of some of her greatest hits. Dressed in a luxurious, champagne-colored robe, Carey kicked things off with “Sugar…