Which of the following poses targets upper body flexibility?

Puppy Pose is a beneficial asana that primarily targets upper body flexibility. This pose involves a forward bend where the arms are extended in front of the body while the torso lowers toward the floor. As a result, this position stretches the shoulders, chest, and upper back, promoting openness and flexibility in these areas.

In contrast, the other poses serve different purposes. Tree Pose primarily focuses on balance and core stability, engaging lower body strength while challenging concentration. Chair Pose is strength-oriented, emphasizing the thighs and glutes, which helps build endurance but does not specifically target upper body flexibility. Plank Pose is mainly a strength-building posture that activates the core, shoulders, and arms to stabilize the body, rather than providing a deep stretch for upper body flexibility.

Thus, Puppy Pose distinctly emphasizes the flexibility of the upper body, making it the most suitable choice for this particular focus.