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>Consider the diagram in <image 1> regarding a mountainous region. The diagram shows the average winter temperature (left-hand y-axis) at different altitudes (x-axis) and the abundance of three tree species (right-hand y-axis) at different altitudes (x-axis). Which species is/are found below an altitude of 500m?
A. Species 1 only
B. Species 2 only
C. Species 3 only
D. Species 1 and 2 only
E. Species 2 and 3 only

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
A
Consider the diagram in <image 1> regarding a mountainous region. The diagram shows the average winter temperature (left-hand y-axis) at different altitudes (x-axis) and the abundance of three tree species (right-hand y-axis) at different altitudes (x-axis). Which species is/are found below an altitude of 500m?
A. Species 1 only
B. Species 2 only
C. Species 3 only
D. Species 1 and 2 only
E. Species 2 and 3 only

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