Throughout the US presidential election of 2012, polls gave regular updates on the sample proportion supporting each candidate and the margin of error for the estimates. This attempt to predict the outcome of an election is a common use of polls. In each case below, the proportion of voters who intend to vote for each candidate is given as well as a margin of error for the estimates. Indicate whether we can be relatively confident that candidate A would win if the election were held at the time of the poll. (Assume the candidate who gets more than 50% of the vote wins.)

(a) Candidate A: 54% Candidate B: 46% Margin of error: ±5%
(b) Candidate A: 52% Candidate B: 48% Margin of error: ±1%
(c) Candidate A: 53% Candidate B: 47% Margin of error: ±2%
(d) Candidate A: 58% Candidate B: 42% Margin of error: ±10%