You are a helpful assistant. When the user asks a question, your response must include two parts: first, the reasoning process enclosed in <think>...</think> tags, then the final answer enclosed in <answer>...</answer> tags.Please provide a clear, concise response within <answer> </answer> tags that directly addresses the question.
system
<image>Huntington disease (HD) is a neurodegenerative disorder characterized by a degeneration of the striatum and cortex of the brain. Patients show motor abnormalities, personality changes, a gradual loss of higher brain functions, and eventually die. Below <image 1> is a family pedigree and an accompanying Southern blot that was obtained with genomic DNA that was probed with a DNA complementary to the gene for the Huntingtin protein. Based on the linked image above, which statement is most likely to be CORRECT?
A. HD is an autosomal recessive disease
B. The huntingtin gene is likely to be located on the X-chromosome
C. A likely cause of HD is an unstable triplet repeat in the HD gene
D. The pattern of bands in the blot is indicative of abnormal splicing of the HD mRNA
E. In most individuals, the region of the HD gene detected by the DNA probe is distributed on six different restriction fragments

Please answer the question with option letter from given choices in the format of Answer: <option letter>. You FIRST think about the reasoning process as an internal monologue and then provide the final answer. The reasoning process MUST BE enclosed within <think> </think> tags. Please answer the final answer within the <answer> </answer> tags.
user
C
Huntington disease (HD) is a neurodegenerative disorder characterized by a degeneration of the striatum and cortex of the brain. Patients show motor abnormalities, personality changes, a gradual loss of higher brain functions, and eventually die. Below <image 1> is a family pedigree and an accompanying Southern blot that was obtained with genomic DNA that was probed with a DNA complementary to the gene for the Huntingtin protein. Based on the linked image above, which statement is most likely to be CORRECT?
A. HD is an autosomal recessive disease
B. The huntingtin gene is likely to be located on the X-chromosome
C. A likely cause of HD is an unstable triplet repeat in the HD gene
D. The pattern of bands in the blot is indicative of abnormal splicing of the HD mRNA
E. In most individuals, the region of the HD gene detected by the DNA probe is distributed on six different restriction fragments

Please answer the question with option letter from given choices in the format of Answer: <option letter>. You FIRST think about the reasoning process as an internal monologue and then provide the final answer. The reasoning process MUST BE enclosed within <think> </think> tags. Please answer the final answer within the <answer> </answer> tags.
val