This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
A child develops blisters on exposure to sunlight' Irregular dark spots on the skin are also found' He is very likely to have a defect in which of the following mechanisms? 
Select and explain. 
A. Nucleotide excision repair, B. Mismatch repair, C. Recombination repair, D. Thymine dimers
A: Nucleotide excision repair
Answer: A: Nucleotide excision repair 
Explanation: The child in question is presenting with features of xeroderma pigmentosa, due to defect in nucleotide excision repair