Merge pull request #32644 from prakul1991/patch-1

Update best-practices.md

Author: GitHubber17

articles/cognitive-services/QnAMaker/Concepts/best-practices.md

@@ -67,6 +67,9 @@ Make sure you are making the best use of the ranking features QnA Maker supports
 ### Choosing a threshold
 The default confidence score that is used as a threshold is 50, however you can change it for your KB based on your needs. Since every KB is different, you should test and choose the threshold that is best suited for your KB. Read more about the [confidence score](../Concepts/confidence-score.md). 
 
+### Choosing Ranker type
+By default, QnA Maker searches through questions and answers. If you want to search through questions only, to generate an answer, use the `RankerType=QuestionOnly` in the POST body of the GenerateAnswer request.
+
 ### Add alternate questions
 [Alternate questions](../How-To/edit-knowledge-base.md) improve the likelihood of a match with a user query. Alternate questions are useful when there are multiple ways in which the same question may be asked. This can include changes in the sentence structure and word-style.