What is the “Bounce Rate” in Google Analytics?

• The number of times unique users returned to your website in a given time period
• The percentage of visits when a user landed on your website and exited without any interactions
• The percentage of total site exits
• The percentage of sessions in which a user exits from your homepage

Correct answer is:

• The percentage of visits when a user landed on your website and exited without any interactions

Explanation: A bounce is a single-page session on your site. In Analytics, a bounce is calculated specifically as a session that triggers only a single request to the Analytics server, such as when a user opens a single page on your site and then exits without triggering any other requests to the Analytics server during that session.

Read more here: https://support.google.com/analytics/answer/1009409