I got on here because I don't understand the question but I did my best to answer because I noticed you asked 3 days ago. IF I'm right the answer is D. My diagram shows A at -50 °C B at 0 °C C at 50 °C D at 100 °C (gas to liquid or liquid to gas) And E at 150 °C So I hope I'm right because I'm answering the same question.
