Multi-select problem: How does the next paragraph end?

How to make a sponge cake
Heat the oven and prepare your pans.
Set the oven to 180 c , 350 f, or gas mark 4. Butter two 9-inch cake pans or 2 12-by-17 inch rimmed baking sheets.

Select from the following. a. Line the bottom of your pans with parchment paper, butter the paper, and then sprinkle flour all over it. Gently shake the flour around and shake the excess out of the pan. b. Scoop out 1/4 cup (120 ml) of all-purpose flour and place this in the bottom of the first 9-inch wide cake pan. Use a rubber spatula to separate the mixture into smaller bowls, which you can cover and store the remaining sugar. c. Place them into the oven and bake the cakes for approximately 1 hour. It's best to roast the cakes for 1 hour before baking them for an additional 4 hours or longer. d. Set the oven thermometer at the lowest temperature possible and check the temperature every hour or so. For an extra stir, build a little fire in the oven's fuel tank to keep the bake time going longer.
a.