Please choose the correct ending to complete the given sentence: Food and Entertaining: [header] How to make a russian apple cake [title] Preheat an oven to 350 degrees/180 degrees celsius. [title] Melt the butter in the microwave and let it cool (but not congeal). [step] Scoop some butter into a small microwave safe bowl.

Ending1: Microwave it for 30 seconds to a minute. Microwave it for longer depending on the type of microwave you have. Ending2: Place a 1/4 pound graham cracker (optional) in the bowl. [title] Blend the butter and graham crackers until smooth. Ending3: Stir, then place the other bowl into the microwave. Heat the mixture until it liquefies. Ending4: You can purchase melted butter online or at a grocery store. Melt it in the microwave for about 20 seconds.

Answer format: ending1/ending2/ending3/ending4