Which of the following mathematicians made major contributions to game theory?

John Von Neumann made major contributions to game theory. He is widely recognized for his groundbreaking work in the field, particularly for his development of the minimax theorem. This theorem revolutionized the way strategies are analyzed in games by introducing the concept of optimal decision-making under uncertainty. Von Neumann's work in game theory has had a profound impact on various fields, including economics, politics, and computer science, and his pioneering efforts laid the foundation for subsequent research in this area.