What happens next in this paragraph?

How to grill souvlaki
Combine the marinade.
Measure 1/2 cup (120 ml) of olive oil into a small bowl. Finely chop 1 small red onion and 2 garlic cloves.
OPTIONS:
(a). Add these to the oil along with the rest of the marinade ingredients. Whisk them until they're combined.
(b). Add these ingredients to the oil, and toss well to combine. For the best flavor, cut the onion into pieces according to the instructions on the package.
(c). Combine the onion with the olive oil and garlic. To ensure that you've followed the package instructions, use the actual recipe.
(d). Use a sharp knife to carefully, but evenly, cut out the head and finely chop the garlic. You can also use chilies instead of onion, if you prefer.
(a).