Respuesta :
Answer:
C. Adding some of the unknown liquid to red litmus paper.
Explanation:
Since the student doesn't know what the liquid is, it is not safe to experiment with it by boiling, cooling, or adding water to it. The safest option would be to add a small bit of the liquid to the litmus paper, which will identify the liquid as neutral, basic, or acidic.
The answer is C. Adding some of the unknown liquid to red litmus paper.