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>2 Calculate the side widths and cross-sectional area of an embankment (Figure 11.13) having the following dimensions:Road width = 20 m;existing ground slope = 1 in 10 (10%);Side slopes = 1 in 2 (50%);centre height = 10 m.<image 1>
A. Side width $w_{1}$ = 37.4 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$
B. Side width $w_{1}$ = 37.5 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$
C. Side width $w_{1}$ = 37.3 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$
D. Side width $w_{1}$ = 37.2 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$

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
2 Calculate the side widths and cross-sectional area of an embankment (Figure 11.13) having the following dimensions:Road width = 20 m;existing ground slope = 1 in 10 (10%);Side slopes = 1 in 2 (50%);centre height = 10 m.<image 1>
A. Side width $w_{1}$ = 37.4 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$
B. Side width $w_{1}$ = 37.5 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$
C. Side width $w_{1}$ = 37.3 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$
D. Side width $w_{1}$ = 37.2 m,Side width $w_{2}$ = 25.0 m,Total area = 418.75 $m^{2}$

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