Final answer:
Without knowing the initial distribution of votes, it isn't possible to determine definitively whether any of the situations (a, b, or c) would result in a majority winner in round two of a plurality with elimination voting method.
Step-by-step explanation:
In a plurality with elimination voting method, which is a type of majoritarian voting scheme, a winner must receive more than 50 percent of the votes to be declared the victor. In the context of the question, producing a majority winner in round two with additional first-choice votes depends on the initial distribution of votes among all candidates. Since the system requires a majority, adding votes to any candidate could potentially create a majority if the added votes bring the candidate's total over 50 percent of the votes. Without knowing the exact numbers, we cannot determine which situation would produce a majority winner in round two. However, in all three cases (a, b, c), it is suggested that votes are added to Ally, Bill, and Twyla. If any of these candidates did not have a majority before and these additional votes push them over 50 percent, they would then be declared the winner.