A nurse is assessing a client who has a chest tube with a water seal drainage system. Upon assessment, the nurse notes tidaling in the water seal. Which of the following is an explanation for the tidaling?

A. Tidaling in the water seal chamber indicates normal fluctuations in pressure as the client inhales and exhales, signifying that the system is functioning properly. B. Absence of tidaling may indicate that the lung has fully re-expanded. C. A loop of tubing below the system can cause drainage issues but does not cause tidaling. D. Clots can partially obstruct the tubing but would not cause regular tidaling.