Final answer:
Sound is the option that is not considered matter, as it does not have mass or take up space on its own. option c is correct
Step-by-step explanation:
option c is correct The student's question asks about which of the given options is not matter. Matter is defined as anything that has mass and takes up space. A radio, a television set, and fire all have mass and occupy space, therefore they are considered matter. However, sound is a type of wave that creates pressure variations in matter like air or water but does not have mass and does not occupy space by itself. Hence, sound is the one that is not matter.