You need to call the Issue API action from the mobile application.

In the context provided by the case study, when calling an API action from a mobile application, the correct format for a POST request to an action in Business Central typically involves specifying the entity (/issues), the ID of the entity (88122e0e-5796-ec11-bb87-000d3a392eb5), and the action to be called (/Copy). The action name should match the exact name as defined in the AL code, which is case-sensitive.

Option A is incorrect because it uses a non-standard format for the action call.

Option B uses the PATCH method, which is generally used for update operations, not for calling actions.

Option C is correct as it uses the POST method, which is appropriate for calling actions, and correctly specifies the entity, ID, and action name.

Option D is incorrect because the action name /copy is in lowercase, while AL is case-sensitive, and it should match the case exactly as defined in the code.

Option E incorrectly adds 'MicrosoftNAV' before the action name, which is not standard for calling actions in Business Central APIs.

Hence, the correct action to use when calling the Issue API action from the mobile application is given in Option C.