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>The bar has a cross-sectional area A and is subjected to the axial load P. Determine the average normal stresses acting over the shaded section, which is oriented at $\theta$ from the horizontal. <image 1>
A. P/(A)*sin(2$\theta$)
B. (P/A)sin^2($\theta$)
C. P/(2A)*sin(2$\theta$)
D. (P/2A)sin^2($\theta$)

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
B
The bar has a cross-sectional area A and is subjected to the axial load P. Determine the average normal stresses acting over the shaded section, which is oriented at $\theta$ from the horizontal. <image 1>
A. P/(A)*sin(2$\theta$)
B. (P/A)sin^2($\theta$)
C. P/(2A)*sin(2$\theta$)
D. (P/2A)sin^2($\theta$)

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