The best way for the person to describe the ingredients for the overnight oats recipe would be:
"Begin by gathering your ingredients. You need oats, milk, yogurt, and your favorite toppings. Strawberries and almonds are just a couple of possibilities. Vanilla and honey can also be used if desired."
This option clearly lists the necessary ingredients while also acknowledging that toppings can vary, which aligns well with the flexibility mentioned in the recipe.