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>Air flows into a heat engine at ambient conditions of 100 kPa, 300 K, as shown in <image 1>. Energy is supplied as 1200 kJ per kilogram of air from a 1500 K source, and in some part of the process a heat transfer loss of 300 kJ/kg air occurs at 750 K.The air leaves the engine at 100 kPa, 800 K. Find the first- and second-law efficiencies
A. 0.32 0.67
B. 0.32,0.74
C. 0.67,0.32
D. 0.74,0.32

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
A
Air flows into a heat engine at ambient conditions of 100 kPa, 300 K, as shown in <image 1>. Energy is supplied as 1200 kJ per kilogram of air from a 1500 K source, and in some part of the process a heat transfer loss of 300 kJ/kg air occurs at 750 K.The air leaves the engine at 100 kPa, 800 K. Find the first- and second-law efficiencies
A. 0.32 0.67
B. 0.32,0.74
C. 0.67,0.32
D. 0.74,0.32

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