[ENG SUB] Nijiyon Season 4 EX. (1 "Mia, Rina, and Ai①") 

Special episode uploaded to YouTube to promote the Nijigasaki Fan Disc, hence the 720p quality.
https://www.lovelive-anime.jp/nijigasaki/bd_fandisc.php

Original: https://youtu.be/j5Ng-HvN_7g