A Three-Year-Old Kid Is Being Assessed for Recurring Respiratory Infections

A three-year-old kid is being assessed for recurring respiratory infections. Five months after his birth, the patient's family emigrated to the United States. Since then, the boy has had many bouts of pneumonia and bronchitis, as well as a chronic cough and failure to grow. His older sibling is in good health. A genetic test finds a mutation in an exon of a gene encoding a transmembrane chloride channel. The aberrant mRNA is extracted from epithelial cells in culture, and its complementary DNA is produced. Base pair length is determined by analyzing amplified cDNA samples from both the patient and his healthy sister using gel electrophoresis and comparing them to DNA fragments of known size. The outcomes are presented below. Which of the following is most likely responsible for this patient's condition?

A) Frameshift mutation
B) In-frame deletion
C) Missense mutation
D) Nonsense mutation
E) Silent mutation
F) Trinucleotide expansion