To Implement a Standard Adminhtml Form for a Custom Data

Multiple Choice

To implement a standard Adminhtml form for a custom data model, which two of the following must you do? (Choose two)

A) Declare your module's block class prefix in the config.xml file.
B) Implement a sub-class of Mage_Adminhtml_Block_widget_Form.
C) Implement a sub-class of Mage_Adminhtml_Block_Form_Abstcact.
D) Create sub-classes of Mage_Adminhtml_Block_Form_Element_Abstract for each form field to be presented.
E) Add a set of configuration values in the module's config.xml defining the form fields to be displayed,