This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to order at chipotle
Choose your " vessel.
You can have a burrito in a large flour tortilla, crispy or soft corn tacos or soft flour tacos. If you don't want any tortillas, you can order a burrito bowl or a salad.

OPT:
[a]. Choose according to what type of taco you want to serve. You can order any combination of both hot and cold tortillas.;
[b]. You can choose to order a " double-wrapped burrito " with two flour tortilla shells at no additional charge. This is best to do if you like more of a bite or if you plan on piling your burrito too high to wrap with just one tortilla.;
[c]. Be sure to reserve separate jars for transportation to the taco location. For convenience, a 20 or 25-gallon (180-90 l) paper tortilla container may work as a container.;
[d]. Make sure the tortilla is thick enough. If you order a thick tortilla, you will have to substitute a sheet of cheese, between 1 and 2 tablespoons of mozzarella cheese , 15 minutes of salsa, and 3 garlic cloves.;
The answer is:
[b].