$($a$)$ No preliminary estimate is available. Find the minimum sample size needed.

$($b$)$ Find the minimum sample size needed, using a prior study that found that $69\%$ of the respondents said they support labeling legislation for GMOs.

$($c$)$ Compare the results from parts $($a$)$ and $($b$).$

$($a$)$ What is the minimum sample size needed assuming that no prior information is available?

$n=($Round up to the nearest whole number as needed.$)$