The developer can turn on outgoing emails on an Adobe Commerce Cloud Staging environment by accessing the Project Web Interface and selecting the Staging environment. Then, the developer can select Configure environment and toggle Outgoing emails On. This will enable the SMTP service for the Staging environment and allow emails to be sent from the application. Verified References: [Magento 2.4 DevDocs] 1

In Adobe Commerce Cloud, email functionality for Staging and Production environments can be controlled through the Project Web Interface. To enable outgoing emails, you can toggle the setting from within the environment configuration.

Using the Project Web Interface:

Navigate to the Project Web Interface, select the Staging environment, and configure the environment settings. Here, you can enable or disable outgoing emails with a simple toggle.

Why Option C is Correct:

This method directly interacts with Adobe Commerce Cloud's environment settings through the GUI. Options A and B are not valid commands in Adobe Commerce Cloud for enabling SMTP or email.