According to the given set up point X, shows a temperature increase. Infrared radiation causes the temperature increase because these waves are produced from the heat radiating bodies and molecules. It is produced by vibration of atoms and molecules. They have moderate frequency range of 3×1011Hz to 4×1014Hz. Other options like ultraviolet rays are absorbed by ozone layer and can reach Earth. Only through ozone holes. Visible light do not produce heat. X-rays are high frequency waves produced by electrons in inner shells. Hence, options (b), (c), (d) are incorrect and option (a) is correct.