The correct answer to the question is : D) Infrared wave.
EXPLANATION :
Before answering this question, first we have to understand thermogram.
Thermograms are the images formed by infrared thermographic cameras.
Infrared thermography ( IRT) is a part of thermal imaging science. The thermographic camera used in this process detects the radiations, and produces the image according to it.
The radiations detected by this camera gives different images for different parts of a body present at different temperatures.
Hence, the correct answer is infrared wave.
