The estimated cost for a national poll is $10 per person interviewed. A project has a budget of $15,000 for the poll. The project manager wants to decide the required number of people to interview for the estimation of the proportion in the population following the presidential primaries in recent weeks. The confidence level must be 90% or above and the margin of error must be 5% or smaller. Give the manager a list of options within the budget and make a recommendation. Justify your answer. Note: don't just consider 95%.