The correct answer is D. Cycling.
A velodrome is a track for cycling, typically oval and banked. It is used for track cycling events such as sprint, keirin, and team pursuit.
Tennis is a racket sport that can be played individually against a single opponent (singles) or between two teams of two players each (doubles). Each player uses a tennis racket that is strung with cord to strike a hollow rubber ball covered with felt over or around a net and into the opponent’s court. The object of the game is to play the ball in such a way that the opponent is not able to play a good return.
Fencing is a physical activity involving the use of edged weapons such as swords, foils, and épées. It is a modern descendant of the ancient art of swordsmanship. Fencing is practiced as a competitive sport, with three main weapons: foil, épée, and sabre.
Boxing is a combat sport in which two people, usually wearing protective gloves, throw punches at each other for a predetermined number of rounds. Boxing is one of the oldest combat sports, and has been practiced for centuries. It is a popular spectator sport, and is also practiced as a form of exercise and self-defense.