You are the center referee in a U19 match between White and Red. After Red scores a goal on AR1’s end of the field, and before the ensuing kick-off, AR2 calls you over for a discussion. AR2 tells you that White’s center forward, #9, should be cautioned for dissent. Since you trust AR2’s judgment, you administer the caution, even though you don’t know the details of what happened. Upon receiving the caution, White #9 looks directly at AR2 and gives a sarcastic thumbs-up, followed by sarcastic clapping, a la Cristiano Ronaldo, which all of the players, team personnel and supporters witness. The rules of competition dictate that a player who receives a caution must be substituted immediately.
What further action, if any, do you take, and why?