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>Hint: Please answer the question and provide the correct option letter, e.g., A, B, C, D, E, at the end.
Question: The diagram shows a rectangle and a straight line $x$, which is parallel to one of the sides of the rectangle. There are two points $A$ and $B$ on $x$ inside the rectangle. The sum of the areas of the two triangles shaded in grey is $10 \mathrm{~cm}^{2}$. How big is the area of the rectangle?
<image1>
Choices:
(A) $18 \mathrm{~cm}^{2}$
(B) $20 \mathrm{~cm}^{2}$
(C) $22 \mathrm{~cm}^{2}$
(D) $24 \mathrm{~cm}^{2}$
(E) It depends on the position of the points A and B. 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
Hint: Please answer the question and provide the correct option letter, e.g., A, B, C, D, E, at the end.
Question: The diagram shows a rectangle and a straight line $x$, which is parallel to one of the sides of the rectangle. There are two points $A$ and $B$ on $x$ inside the rectangle. The sum of the areas of the two triangles shaded in grey is $10 \mathrm{~cm}^{2}$. How big is the area of the rectangle?
<image1>
Choices:
(A) $18 \mathrm{~cm}^{2}$
(B) $20 \mathrm{~cm}^{2}$
(C) $22 \mathrm{~cm}^{2}$
(D) $24 \mathrm{~cm}^{2}$
(E) It depends on the position of the points A and B. 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