Answer:
you will need to look at the calories and then the ingredients and how much of each ingredients there is.
From experience with my best friend, I´d say C.
A serving size is how much of it you take for yourself, and portion size is how much out of the whole thing.
For example cheeto puffs, a serving size would be one of those little mini bags. but a portion, is probably just a section of the chips. mean serving size is how many youre going to eat but portion is just a chunk out of the entire thing