Below is an example of an attention check setup. If the respondent fails to select none of the above they are screened out.
First, set logic that skips the respondent to the end of their current block if they fail the attention check. This prevents the respondent from being exposed to additional questions. The same process would be applied for an unqualified response to a demographic question, for example.
Next, select Survey Flow from the top of the page. You'll want to locate the block that contains your screen-out question and set the logic necessary to sent them to the screen-out URL.
The image below illustrates that both screen-out and completion blocks (End of Survey blocks) will look the same, but should contain different URLs