Which action can cause the data stored in cookies and local storage to be erased?

The action that leads to the data stored in cookies and local storage being erased is clearing browser cookies. When a user chooses to clear cookies, it specifically targets any data that has been saved in cookies, such as session information, preferences, and tracking data. This action is often undertaken for privacy reasons or to resolve issues related to website performance.

Cookies are designed to hold information that helps in user sessions or tracking, and clearing them will directly lead to the removal of this stored data. Local storage, while more persistent and typically not directly affected by clearing cookies, might also be cleared depending on the specific browser settings and options chosen for clearing browsing data. However, the explicit action of clearing browser cookies is a direct cause for the erasure of the cookie data, making this option notably correct.

In contrast, upgrading the browser version does not inherently affect cookies or local storage; switching user accounts may maintain cookie data for the current user profile; and changing server settings does not influence stored client-side data like cookies or local storage.