The correct answer is option 4, white.

Heat radiation is the emission of electromagnetic waves, including light, from an object due to its temperature. The color of heat radiation depends on the temperature of the object. Objects at lower temperatures will emit radiation in the infrared spectrum, which is not visible to the human eye. As the temperature increases, the color of the radiation changes to red, orange, yellow, and eventually to white.

Option 1, blood red, represents a lower temperature as it indicates radiation in the red spectrum. Option 2, dark cherry, is a similar reddish color but may indicate a slightly higher temperature than blood red. Option 3, salmon, is also a warmer color in the red-orange range.

White, option 4, represents the highest temperature as it is the color of radiation emitted by extremely hot objects. When an object reaches a high temperature, all visible colors of light are emitted, which combine to form white light. White is often associated with the highest temperatures because it encompasses the full spectrum of visible light.