Which of the following techniques can help reduce stress through relaxation?

Progressive muscular relaxation is a technique specifically designed to reduce stress through a process of systematic tension and relaxation of different muscle groups in the body. This method encourages individuals to focus on the sensation of relaxation, which helps to decrease physiological tension and promotes an overall sense of calm. By consciously tensing and then relaxing each muscle group, practitioners become more aware of physical sensations, leading to a decline in stress levels.

In contrast, prolonged physical activity can sometimes lead to increased stress if not done mindfully, while multitasking generally increases cognitive load and can elevate stress rather than reducing it. Continuous thinking without periods of mental rest may also contribute to anxiety rather than alleviating it. Therefore, progressive muscular relaxation is the most effective among the options presented for achieving a state of relaxation and stress reduction.