The sample size 230 here.
Among them 62% is them in the upcoming election.
Hence they are
[tex]\frac{62}{100}\times230=142[/tex]in number.
now we have to find the population standard deviation with the sample size 230.
It is given by
[tex]\frac{142}{230}=0.62[/tex]Hence the margin of error is given
[tex]0.62\times10=6.2[/tex]Hence the closest margin value is 6.4%