Final answer:
On a single VF page, we can use one controller, which can be a standard controller or a custom controller. A standard controller is associated with a specific standard object, while a custom controller is used for interacting with multiple objects or custom logic.
Step-by-step explanation:
On a single Visualforce (VF) page, we can use one controller. A VF page can have only one associated controller. However, the controller can be a standard controller or a custom controller.
A standard controller is used when the VF page is associated with a specific standard object in Salesforce, such as Account or Contact. In this case, the standard controller handles the logic for that object.
A custom controller is used when the VF page needs to interact with multiple objects or perform some custom logic. You can define a custom controller class for this purpose.