Answer:
Total 2*2*3 = 12 outcomes
------------------------------------------------------------------------
> thick, white, pepperoni
White > > thick, white, cheese
> thick, white, vegetarian
Thick > >
> thick, red, pepperoni
Red > > thick, red, cheese
> thick, red, vegetarian
------------------------------------------------------------------------
> thin, white, pepperoni
White > > thin, white, cheese
> thin, white, vegetarian
Thin > >
> thin, red, pepperoni
Red > > thin, red, cheese
> thin, red, vegetarian