A Selected Response interaction presents a set of choices to the candidate. The candidate's task is to select one or more of the choices to form a correct response. The interaction is always initialized with no choices selected.
Your item may also require the selection of multiple choices within the response (sometimes known as "Choice Multiple"). For example:
Creating a Selected Response Interaction
In the item editor, add a Stem element. In the Select Interaction Type window, select the Basic tab, followed by Selected Response. Click Create Interaction.
In the Stem Prompt area , type in a question (ex: "Which of the following elements are used to form water?"). Click the Add Text button .
The text appears in the content area of the stem prompt.
In the Selected Response (Choices) area, enter various answers , one by one (clicking Add Text  between each choice) to add them. Each choice appears with a letter and a key symbol next to it.
Click the key icon to the left of the choice that is the correct answer .
Customize - Multiple Correct Answers
By default, a Selected Response interaction only allows one choice to be selected as the key (correct answer).
To allow the candidate to select more than one choice:
Click the Customize  button, then click the "Allow Multiple Keys" check box . Click the Save button . Then click on each key that corresponds to the correct answer(s) .
Customize - Number of Choices to Make
You can also specify the number of choices a candidate can select. Click Customize, and in the "Choices" section, enter a minimum number of choices that can be selected (Min) and a maximum number of choices that can be selected (Max). The candidate is then required to choose at least "Min" choices and no more than "Max" choices.
By default, a Selected Response item is worth 1 point. If you allow multiple keys, it is worth 1 point and the candidate must get all answers correct to get 1 point. However, scoring can be customized. Refer to Response Scores for more information.
Rationales explain why a candidate might have chosen a particular response. You can add rationales for one or more of the selected response choices. To do so:
- Click Customize and choose "Enable Rationales."
- Rationale fields appear for each response. Enter and add text, images, equations  or use the Text Editor , just as you would for the stem.
Once you are finished adding rationales, you can see them by rendering the item and looking at the Editorial tab :
If you would like the Question and Test Interoperability (QTI) version of a Selected Response item to have the answer choices presented in a different order each time the item is presented to a candidate, click Customize  and enable "Allow Shuffle" 
You won't see shuffled answers in the preview of the item, but the shuffling attribute is associated with the QTI version of the item. The shuffle attribute tells a delivery system to shuffle the order of the choices before displaying them to the candidate. (Note that the shuffle attribute ensures that the initially presented order is never the correct answer.)
Creating a Selected Response Item (2m 17s)
Adding Rationales to Item Responses (1m 52s)