A) Mumbai Indians
B) Chennai Super Kings
C) Kolkata Knight Riders
D) Royal Challengers Bangalore
Explanation: Former South Africa captain AB de Villiers has announced his retirement from all forms of cricket on November 19, 2021. He had already retired from international cricket in 2018. However, AB de Villiers was still playing in the Indian Premier League (IPL) for Royal Challengers Bangalore (RCB), ever since joining the franchise in 2011.