The correct option is B.
From the information given in the question, we can see that only the rich in the society had telephone in their homes during the time of the said presidential election. Thus, the presidential candidate that was ahead in telephone polls was actually getting in touch with the rich only; he was not getting through to the larger part of the society, who are poor. Since both the poor and the rich are going to vote in the presidential election, it means that Dewey campaigned to only a subset of the society, that was why he was defeated during the election.