Question

the melting point is at point ______

Explanation:

Step1: Recall melting - point concept

The melting - point is the temperature at which a solid changes to a liquid. On a heating - curve, it is represented by the horizontal line during the phase change from solid to liquid.

Step2: Identify the relevant horizontal line

In the given heating - curve, the horizontal line segment BC represents the melting process where the substance is changing from solid to liquid while the temperature remains constant. The starting point of this horizontal line (point B) is the melting point.

Answer:

C. B