(Next time please insert a picture of The graph regarding to your question)
Answer: The answer is (A)
Step-by-step explanation:
QR- Liquid Only
RS- Phase Change Liquid-Gas
ST-Gas Only
This graph does not begin in the solid phase of water. It begins at 40 degrees Celsius in the liquid phase. Plateaus are phase changes. In this case, it’s a phase change from liquid to gas.