In order to show only filtered responses to your open ended question you can use the "Star" tool.
1. Go to your question's presentation page and switch the "Which responses to show" option from "All" to "Curated" in the presentation settings. This will limit the responses that are shown to only the ones you star from the dashboard.
2. Go to your account, open the question and star the responses that you want to show on the presentation page. Once starred, the responses will immediately appear on the presentation page. No responses will be shown unless you star some of them. Once starred, the response will move to the "starred" tab in the list.
Note: if you switch the presentation mode setting back to "All", all the responses will show up on the screen including the ones you had starred.