At melting point,

Options

A. kinetic energy remains constant and potential energy increases
B. kinetic energy increases and potential energy remains constant
C. both potantial energy and kinetic energy increase
D. potential energy increases with a decrease in kinetic energy

Explanation

### Step-by-Step Solution:

1. **Understanding Melting Point**: The melting point is the temperature at which a solid turns into a liquid. For ice, this occurs at 0 degrees Celsius.

2. **Heat Absorption**: At the melting point, ice absorbs heat from the surroundings. This heat is necessary for the phase change from solid (ice) to liquid (water).

3. **Change in Potential Energy**: As ice absorbs heat, its potential energy increases. This is because the molecules in the solid state (ice) are held together by strong intermolecular forces. When heat is absorbed, these forces weaken, allowing the molecules to move apart, thus increasing potential energy.

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