Fact 1: Killing microorganisms in food can be used to extend the shelf life of that food. Fact 2: Irradiation kills microorganisms that spoil food. Given the two facts above, what can be used to extend the shelf life of food?

Pick your answer from:
(1). Cooking;
(2). Enzymes;
(3). rays or beams;
(4). irradiation;
(5). leaving food at room temperature;
(6). Dehydration;
(7). eating food;
(8). grinding food;
The answer is:
(4).