"One row at a time" is a unique style that can be applied to 2-dimensional single-select elements. The question will only display the first row and when the respondent selects an answer the next row will appear, until each row is answered.
The following examples highlights the one row at a time style.
Applying One Row at a Time to a Question
To apply the one row at a time style to a question, select the single-select question so it appears in the stage. Then click on the "Basic" style link found in the top, right corner of the question.
The "Question Display Options" window will appear. Select "One Row at a Time" in the dropdown menu. Then select "Save" and the style will be applied to the question.
You can preview the element at any time by clicking on the "Preview" link located at the top right corner of the element. To find out more about the previewing an element, click here.