“那儿(nàr)” vs. “哪儿(nǎr)” – Which One Should I Use?

You may often hear Chinese people saying “那儿(nàr)” and “哪儿(nǎr)” when talking about places. So what are the differences between them? Please choose the correct answer to fill in the blanks. Zhang Ming met Wang Li on his way home, so he came up to …