Default selection on Dropdown visuals

Hello,

I am using Dropdown and Search Widget for selective purposes and filtering down the data of Line chart with respect to timeline.

At the moment, when the graph is loaded the line chart displays all the available data with respect to time which is quite confusing for viewers.

Ideas:

It would be good is line chart disappear if there is default (none) option is selected.

or

There should be an option for a default selection so while seeing a graph only that particular data will be filtered.

Thanks and look forward to your comments.