Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to make gyudon [title] Slice the beef and vegetables. [step] Use a sharp knife to shave the beef into very thin slices. Cut the onion and shiitake mushrooms into moderately thin slices, as well.

Ending1: [title] Heat oil in a skillet over medium heat. [step] Set aside for about a minute so the pot can drain completely. Ending2: [substeps] To save yourself time and effort, ask the butcher to slice the beef very thinly before packaging it. If the butcher does not slice the beef, freeze it for 1 hour before slicing it yourself. Ending3: Finally, cut the mushrooms into quarters and the beef. Mash the ingredients together into a nice pea-sized bowl until it's smooth and light. Ending4: You can also use a meat tenderizer instead, that's gentler on the meat and also less fancy. [substeps] Don't use the steak or pound of beef in this recipe as the meat will soften more easily than the tenderizer.

Answer format: ending1/ending2/ending3/ending4