Question: Why do Tiafoe and Federer tap each other in the fourth game of the second set?
(A) Tiafoe shows his apology for hit the ball on Federer's abdomen
(B) Tiafoe encourges Federer after winning the game
(C) Tiafoe shows his apology for hit the ball on Federer's head
(D) Tiafoe shows his apology for hit the ball on Federer's leg
Answer: C