Please choose the correct ending to complete the given sentence: Food and Entertaining: [header] How to make rainbow chocolate chip cookies [title] Prepare the oven and tray. [step] Preheat the oven to 350 degrees fahrenheit or 176 degrees celsius. Cover a baking tray with parchment paper or spray non-stick greasing spray on it.

Ending1: Spray the tray with nonstick cooking spray. [substeps] You don't need to cover the tray at all, just spray the baking tray with non-stick cooking spray to help make sure it's dry. Ending2: Prepare the cookie sheet by laying out baking paper or using a baking tray. [substeps] Make sure that the tray is shallow enough for the cookie sheet to sit perfectly. Ending3: [title] Combine the flour, baking soda, and cornstarch with a whisk. [step] Stir until the dry ingredients are mixed properly. Ending4: [substeps] Ensure the sheet of parchment paper is easily accessible by opening it to show your cookie mix pile. [title] Mix the chocolate chips in a bowl.

Answer format: ending1/ending2/ending3/ending4