Which percentage is the right answer

This is a bad question.

The real answer is any of them may be the actual percentage, the true population mean.  Probability and statistics often don't rule events out entirely; they just tell us some events are very unlikely.  For example here all we know is there's a 95% chance the true percentage is within .  But there's a 5% chance it isn't, so those other percentages are still possible.

The question seems to want to ask which percentage falls within the 95% confidence interval.  That's between 78-8=70% and 78+8=86% so the answer is

C 72%