Make a matrix question required
Because matrix questions can contain multiple segments and because the type of data in segment can vary, there is no setting the make a matrix question required. Instead, the required constraints are defined for each segment, which provide maximum flexibility to choose which data should be entered and which data can be skipped by the respondent.
Segments with radio buttons or check boxes
The minimum number of options can be set per row, per column, and per segment.
Segment with text, dates, numbers, or drop down lists
In addition to the minimum number of answers per row, column, and segment as described above for segments with radio buttons or check boxes, specific column in the segment can be required.