What inborn error of metabolism affects pancreatic secretion of digestive fluids?

Out of the following given choices;

a)      phenylketonuria (PKU) b) diabetes mellitus c) cystic fibrosis d) ketoacidosis

The answer is C. It is a defect of the chloride ion channels (due to mutation of the CFTR gene) that help with the concentration and secretion of all the fluids in your body affecting mostly the lungs, pancreas, liver, kidneys, and intestine, hence causing excessive production of mucus that clogs up the organs.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

the areas around the equator