This method will guide you to count the YES and NO answers with the COUNTIF function, and then add a pie chart based on the counting results. Please do as follows:

1. Beside the questionnaire table, create a table for counting the YES and NO answers as below screenshot shown.

2. Select the cell you will place the counting results of YES answer, type the formula =COUNTIF($B$2:$B$13,D2), and then drag the AutoFill Handle down to count the NO answer. See screenshot:
Note: in the formula =COUNTIF($B$2:$B$13,D2), $B$2:$B$13 is the list with YES and NO answers, D2 is “Yes” answer, and you can change them as you need.

3. Select the counting table, and click Insert > Insert Pie or Doughnut Chart (or Pie) > Pie. See screenshot:

Now the pie chart for all YES/NO answers is created. See screenshot:

You can also create a pie chart for the YES/NO answers with a pivot chart in Excel. Please do as follows:

1. Select the questionnaire table, and click Insert > PivotChart (or PivotTable) > PivotChart. See screenshot:

2. In the Create PiovtChart dialog, please check the Existing Worksheet option, specify the first cell of destination range, and click the OK button. See screenshot:

3. In the PivotChart Fields pane, please drag the Answer filed to both Axis and Values sections. See screenshot:

4. Now the pivot chart is created. Right click the series in the pivot chart, and select Change Series Chart Type from the context menu. See screenshot:

5. In the Change Chart Type dialog, please click Pie in the left bar, click to highlight the Pie chart in the right section, and click the OK button. See screenshot:

Now the pie chart for the YES/NO answers is created. See screenshot:

How to create pie of pie or bar of pie chart in Excel?