Full Detailed in Depth Explanation:

In Oracle HCM Cloud, line managers can initiate promotions for subordinates via specific navigation paths, but not all options listed are valid methods.

Option A ("The line manager can select My Portrait and click Promote under the Actions menu"): Incorrect (thus an answer). "My Portrait" refers to the manager’s own profile, not the subordinate’s, so this cannot be used to promote John.

Option B ("The line manager can enter Promote John in the Person Gallery Keyword Search, which launches the promotion process automatically"): Incorrect (thus an answer). The Person Gallery Keyword Search allows searching for people or actions, but typing "Promote John" does not automatically launch the promotion process; it requires further navigation.

Option C ("The line manager can promote John from Organization Chart Actions under Personal and Employment"): Correct (not an answer). The Organization Chart provides actions like Promote for subordinates, a valid method.

Option D ("The line manager can access John's portrait and click Promote under the Actions menu"): Correct (not an answer). Accessing John’s portrait in the Person Gallery and selecting Promote from the Actions menu is a standard method.