Final answer:
Retail websites track consumer preferences using cookies, which store data about online activities to enhance user experience.
Step-by-step explanation:
Retail websites often track the consumer's preferences by using cookies. Cookies are small pieces of data that are stored on your device by a web server through your browser. These are used to remember your online activities, such as items added to a shopping cart, login information, or pages you have visited. This helps the website to provide a more personalized and efficient user experience when you return to the site.
It is important to note that cookies are different from other options listed like browsers, passwords, or firewalls. Browsers are software applications used to access the internet, passwords are used for authenticating and accessing secured resources, and firewalls are security measures that protect a network by filtering incoming and outgoing traffic.