Hi,
I was also stuck between A & C. But I remember, Stacey mentioned in earlier post that 'comma preposition' set up is an adverbial modifier...means modifies the previous clause. (read:
https://www.beatthegmat.com/ing-modifier ... 38943.html
eg: The diet of the ordinary Greek in classical times was largely vegetarian - vegetables, fresh cheese, oatmeat, and meal cakes, with meat as a rarity. Here 'with meat as a rarity' modifies "the diet...was largely vegetarian".
Taking a clue of this, I felt 'with the intention' modifies "Asset allocators create"....not portfolios. It makes sense.
Secondly, for C....in the same post "comma -ed" modifier modifies immediate preceeding noun....in this case "mutual funds"...does not make sense.
I selected A. Pls correct me.