What is the last step to complete before finishing the app development?

The correct answer is deploying the application to production, as this is the final step that signifies the app is ready to be accessed by the end users. This action makes the application live and functional, allowing users to use it in their day-to-day activities. After thorough testing and development, deployment is the culmination of all the previous efforts, ensuring everything meets the necessary standards and works seamlessly in the live environment.

While options like user testing, adding a logout button, and integrating translation actions are vital steps within the app development process, they typically occur before deployment. User testing helps identify any final adjustments needed, adding a logout button is part of finishing touches for user experience, and translations ensure the app is accessible to a wider audience. However, these actions are completed prior to the application being deployed, making production deployment the definitive last step.