Answer :
Id say Router is the answer based on your Question.
Router - is a device used to host a network signal which people will require the SSID(network-name) to connect to.
It is a bit confusing because the correct answer is SSID which leads me to belive Public Wi-Fi is also correct..
Router: it can host the local network at home (via wifi) and through NAT (network area translation), route local traffic to internet traffic