HELPP PLEASE!! Which of the following statements best explains why cystic fibrosis forms within someone diagnosed with this disease?

A
One segment of DNA that builds respiratory and digestive system body parts reads GAG/CTC. This gene becomes transcribed into the RNA codon GAG and leads to the amino acid Glu within the protein.

B
The amino acid Phe becomes duplicated leading to an overabundance of this substance within the incorrect protein.

C
The segment of DNA normally containing TTT/AAA is deleted (deletion mutation). When transcribed, the RNA codon UUU is now missing causing an entire shift in RNA to the left. This ultimately results in the amino acid Phe being absent within its appropriate location.

D
The surface of ribosomes become enlarged leading to the incomplete translation of RNA into proteins.