Patients with cystic fibrosis are very susceptible to bacterial infections. Which of the following best describes why this is the case?

A) Water cannot be pumped into the cells from the mucus lining.
B) Water cannot be pumped out of the cells and into the mucus lining.
C) Transport protein cannot pump sodium ions out of the lung cells and into the mucus lining; the water then remains in the cells.
D) Transport protein cannot pump chloride ions out of the lung cells and into the mucus lining; the water then remains in the cells.