B. positive result
When on the lookout for redundancies, one should be on the lookout for words that say the same (or similar) thing or for a modifier that unnecessarily modifies a word because, by nature of the definition of the modified word, it is obvious. For instance, it would be redundant to say “wet water.” That said, the redundancy is with the word pair “positive result” because a “result” is an outcome that is positive; an outcome that is negative would be a consequence. Thus, it is not necessary to say “positive result” because results are, by definition, positive.
It is redundant because the word openness already presupposes vastness.