In 1945, a Raytheon engineer named Percy Spencer was fiddling with energy sources for radar equipment. While testing a new vacuum tube, he discovered that a chocolate bar he had in his pocket melted more quickly than he would have expected. He became intrigued and started experimenting by aiming the tube at other items, such as eggs and popcorn kernels. All of the things he aimed at responded as it they were being cooked. What can Percy Spencer infer from this observation?
A.) The energy source he was using had no effect on other substances.
B.) The energy source he was testing was able to cook foods.
C.) The energy source he was testing created heat.
D.) The energy source he was testing made substances respond as if they were being heated.