Which one of the following choices can be added to increase the "creaminess" and nutritional value of soups without adding fat?
a. creamed corn
b. nonfat milk
c. cornstarch
d. pureed root vegetables

All of the above would give some nutritional value.  I would have to say that cornstarch and creamed corn would give mostly added calories with small amount of vitamins. Cornstarch does not even give fiber, which at least the creamed corn does.
The non-fat milk would add protein, vit D and calcium, no fiber.
Pureed root vegetable would give the most vitamins, and fiber to dish.
They all work to increase creaminess with out added fat.
So basically all do add something, some more than others, and different nutrients.