Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to calculate pi by throwing frozen hot dogs [title] Select a food item to throw. [step] There are a couple of qualifications. First, it must be long, thin, hard, and straight, like a frozen hot dog, for example.

Ending1: Second, it must be simple and fairly metal. If it's not chunky enough, you can only take it as a bone. Ending2: It must have real food (meat or dairy). Next of all it must have added " 1 " to it, which is abbreviated pi. Ending3: Second, it must be a reasonably stiff item. Third, it should be somewhere between 15 and 20 cm (6-8 inches) long; the experiment can be performed otherwise, but read on, and you will see why this size is optimal. Ending4: It must not fall apart, it must be long and flexible. Second, the box must have an indentation, which equals pi.

Answer format: ending1/ending2/ending3/ending4