Answer: Blank 1
Explanations:
Blank 1: It's obvious that the option choices are fiber and protein, because the new cereal is nutritious and has whole-grain wheat.
Blank 2: Glucose isn't that good for you when it comes to cereal, so this wouldn't be it because the cereal, and minerals doesn't even sound right for the last option.
Blank 3: Neutralized and refined doesn't make sense in the first two blanks anyway -.-
I hope they're not wrong. If so, please tell me! :>