What action should you take to change macro security settings to disable all macros with a warning?

To change the macro security settings to disable all macros with a warning, you should select the option that specifically states to disable all macros with notification. This setting will effectively disable macros, which is a safer choice, while still allowing users to receive a warning when macros are present in documents. Thus, users can choose whether to enable them on a case-by-case basis, providing a balance between security and functionality.

The other choices do not fulfill this requirement. Selecting "Enable all macros" would allow macros to run freely without any security checks, which can pose a risk. Choosing "Disable all macros without notification" would prevent macros from running without any indication, preventing user awareness of macros in documents. Opting for "Enable macros only for trusted documents" would allow macros to run if the document is deemed trusted, further increasing risk if untrusted documents are opened.