You wish to have your own start up business in a new city. You will :

The correct choice is: You will select a sample area and sample size of people for survey and take decision accordingly

‘You will select a sample area and sample size of people for survey and take decision accordingly’ is the best choice. A sample survey gives reliable market information at reasonable cost. Starting blindly is risky, surveying a whole state is impractical, and asking only relatives gives biased views.