What are airway clearance techniques used for?

Airway clearance techniques are specifically designed to help clear mucus and secretions from the airways, making option B the most accurate answer. These techniques aim to improve ventilation, facilitate breathing, and prevent the accumulation of mucus that can lead to infections or increased respiratory complications. They can include various methods such as chest physiotherapy, postural drainage, and device-assisted techniques like vibratory vest therapy.

The other options focus on unrelated functions. Diagnosing lung diseases involves diagnostic tests and imaging techniques rather than clearance methods. Enhancing athletic performance pertains to conditioning and training rather than airway management. Additionally, increasing lung size is not a primary goal of airway clearance techniques; rather, they focus on maintaining clear and unobstructed airways to optimize breathing efficiency.