What should you do to correct the problem with an email button caption?

Answer options:

A.Use App Checker
B.Add &ribbondebug=true to the app’s URL
C.Use Ribbon Workbench
D.Use Command Checker
E.Add &ribbonbench=true to the app’s URL
F.Edit Client script

Correct Answer: C 
Power Apps provides functionality to add the buttons to the ribbon in your model-driven apps. One of the tools that helps makers and developers to accomplish this procedure more easily is the Ribbon Workbench. You can add the Ribbon Workbench solution to your environment and use this tool for creating and editing the buttons. 
If you open your solution in the Ribbon Workbench (Number 1), you can select the button (Number 2). The workbench opens the Control properties (Number 3) panel on the right and Solution elements (Number 4) on the left. If you select the button under the Buttons (Number 5), the workbench also opens to edit the properties control panel (Number 5). And you can correct the button`s label (Number 6). Next, you publish the solution (Number 1). 

All other options are incorrect. 
For more information about the Ribbon commands, please visit the below URLs: 

https://docs.microsoft.com/en-us/powerapps/developer/model-driven-apps/define-ribbon-commands
https://ribbonworkbench.uservoice.com/knowledgebase/articles/358664-create-a-command-bar-button-for-your-custom-acitiv
https://docs.microsoft.com/en-us/powerapps/developer/model-driven-apps/customize-commands-ribbon