Answer:
Option B is correct.
Explanation:
We are given that,
The reporter wants to estimate the percentage of registered voters who will vote for a particular candidate in the upcoming election.
It is required to find the most accurate method to help him find the accurate percentage.
Out of all the options, the least likely to give biased result is option B.
That is, 'He could take a random sample of registered voters, and then calculate the percentage of the sample who will vote for the particular candidate'.
Hence, option B is correct.