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>Load moves along the three-hinged,  parabolic arch ABC, shown in Figure P12.24.  Construct the influence lines for the reactions at  C, and shear, axial load and moment at point D.  The equation for the parabolic arch is y = 4hx2 /L2 . If a point load P = 3 kips is applied at B,  compute shear load at D.<image 1>
A. -1.84k compr
B. -1.94k compr
C. -1.74k compr

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
Load moves along the three-hinged,  parabolic arch ABC, shown in Figure P12.24.  Construct the influence lines for the reactions at  C, and shear, axial load and moment at point D.  The equation for the parabolic arch is y = 4hx2 /L2 . If a point load P = 3 kips is applied at B,  compute shear load at D.<image 1>
A. -1.84k compr
B. -1.94k compr
C. -1.74k compr

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