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_Abstract.
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.