Please choose the correct ending to complete the given sentence: Health: [header] How to make acidophilus yogurt [title] Combine 4 cups (950ml) of milk and 3/4 cups (120 g) of powdered milk (if not using whole milk) in the saucepan. [step] Set the burner to medium heat and place the saucepan on the burner. [title] Whisk the mixture constantly to keep it from sticking to the pan.

Ending1: [step] If the mixture is too liquid, add more milk. Keep whisking and stirring until the mixture reaches a smooth consistency. Ending2: [step] Do not stop whisking until the mixture thickens and has turned a deep butter gray. [title] Insert a lemon slice into the melted mixture and transfer it to a blending dish. Ending3: [step] Turn the heat to medium-high and keep whisking. [substeps] You'll find the mixture thickening and forming a light adhesive on the pan. Ending4: [step] Gradually heat the milk to 180 to 190 degrees fahrenheit (82 to 87 degrees celsius). Determine the temperature by inserting the instant read thermometer in the milk periodically.

Answer format: ending1/ending2/ending3/ending4