The correct answer is option 'D', which states that the attribute "selected" is not used for the radio type.

Explanation:
- The radio type in HTML is used to create a set of radio buttons, allowing users to select only one option from a list.
- Radio buttons are often used in forms where users need to choose a single option from multiple choices.
- To create a radio button, we use the tag with the "type" attribute set to "radio".
- The radio button has several attributes that can be used to define its behavior and appearance.
- Let's review the attributes mentioned in the question and explain their usage:

a) name attribute:
- The "name" attribute is used to specify the name of the radio button group.
- All radio buttons with the same name attribute belong to the same group.
- This attribute is important because it allows the browser to determine which radio buttons are related and enables the user to select only one option from the group.

b) value attribute:
- The "value" attribute is used to specify the value associated with the radio button.
- When the form is submitted, the selected radio button's value is sent to the server.
- The value attribute is important for processing user input.

c) checked attribute:
- The "checked" attribute is used to pre-select a radio button when the page loads.
- By default, none of the radio buttons are selected.
- Using the "checked" attribute, we can set a default selection for the radio button group.

d) selected attribute:
- The "selected" attribute is used with options in a dropdown list () and not with radio buttons.
- It determines the default selected option in the dropdown list.
- However, it is not applicable to radio buttons.

In summary, the attribute "selected" is not used for the radio type. It is used with dropdown lists instead.