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>According to the results in Model 2, if we want to test the null that the Coefficient associated to a level C3 branch is equal to that of a C4 branch, and knowing that $Prob[t(545) $ \leqslant $ -2]=0.025$ <image 1> 
A. The null must be rejected at the 5% significance level.
B. The null cannot be rejected at the 5% significance level.
C. There is not enough information in the problem statement to test this null.

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
According to the results in Model 2, if we want to test the null that the Coefficient associated to a level C3 branch is equal to that of a C4 branch, and knowing that $Prob[t(545) $ \leqslant $ -2]=0.025$ <image 1> 
A. The null must be rejected at the 5% significance level.
B. The null cannot be rejected at the 5% significance level.
C. There is not enough information in the problem statement to test this null.

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