Which of these devices is usually the default gateway for most home networks?
a. a workstation
b. a server
c. a smartphone
d. a wireless router?

D- WIRELESS ROUTER

Explanation:

A wireless router is a device which performs the functions of a router and that of a wireless access point. It's provide access to the Internet.

Wireless router work as a router because it is an electronic device that sends data from the internet cable to a device as a wireless access point so that the data can be shared through radio signals instead of another cable in which it receive information and transmit the information to the internet. The router then creates and communicates with your home Wi-Fi network using built-in antennas. As a result, all of the devices on your home network have internet access.

Therefore the default gateway for most home networks is WIRELESS ROUTER.