A patient presents with extreme photosensitivity, numerous skin cancers at an early age, and neurological abnormalities. Genetic testing reveals a defect in a DNA repair pathway responsible for excising bulky adducts, such as pyrimidine dimers formed by UV radiation. Which repair mechanism is most likely impaired?
✓ Correct Answer: Option B
Xeroderma Pigmentosum is characterized by a defect in Nucleotide Excision Repair (NER), a critical pathway for removing bulky DNA lesions such as pyrimidine dimers induced by UV light. This leads to extreme photosensitivity and high risk of skin cancers.