Explanation
Marketing Cloud Account Engagement sets cookies on visitors' browsers to track their activities. Cookies are small bits of text that a website leaves with the browser so the website can remember who the visitor is.
Cookies are the most common method used to identify users online and provide a personalized browsing experience. Marketing Cloud Account Engagement uses cookies to track visitor behavior on the website, such as pages visited, forms submitted, or files downloaded. Marketing Cloud Account Engagement also uses cookies to associate visitors with prospects once they fill out a form or click on a tracked link in an email.
Option A is not correct because UTM parameters are not set by Marketing Cloud Account Engagement, but by the marketer who creates the URL with query strings that indicate the source, medium, campaign, and other information of the traffic. Option B is not correct because tracking pixels are not set by Marketing Cloud Account Engagement, but by the email client that renders the email with a hidden image that sends a request to Marketing Cloud Account Engagement's server and records the open event. Option D is not correct because Google Analytics tracking code is not set by Marketing Cloud Account Engagement, but by the website owner who embeds the code on the website to collect and analyze web traffic data. References: The Ultimate Marketing Cloud Account Engagement Admin Guide to Web Tracking Cookies - The Spot, How to Run an A/B Test in Marketing Cloud Account Engagement: A Step by Step Guide (2022), The Basics of A/B Testing in Marketing Cloud Account Engagement - The Spot