Who can add Projects if the subscription is paid for by the practice?

The correct answer is that staff with access to billing accounts can add Projects when the subscription is paid for by the practice. This is because access to specific features or functionalities in a software like Xero is typically determined by the level of access granted within the organization's subscription settings.

Staff with access to billing accounts usually have elevated permissions that allow them to manage financial aspects of the subscription, which includes the ability to add or modify projects within Xero. This access is necessary since adding projects often involves considerations of resource allocation, budgeting, and tracking financial performance, functions that are typically handled by those who manage billing and financial accounts.

Other staff members may not have the necessary permissions unless specifically granted. Therefore, this choice aligns with the administrative capabilities granted to those managing financial and subscription details in the practice's Xero account.