All of the given responses describe changes that occur at the microscopic level when gallium melts in a person's hand. However, the most accurate response to focus on regarding the process of melting is:
The gallium atoms will gain kinetic energy.
When gallium melts, the temperature increases, which raises the kinetic energy of the atoms, causing them to move more freely and transition from a solid to a liquid state. While the gallium atoms also increase in temperature and their average movement speeds up, the key change during melting is the increase in kinetic energy.