Selected item DropDownList

When i know what data is bound to a dropdownlist, and i know which items was chosen, how can i get that item selected in a dropdownlist?
Basics:

<asp:DropDownList ID="ddl" runat="server">
      <asp:ListItem Value="1" Text="Option A" />
      <asp:ListItem Value="2" Text="Option B" />
      <asp:ListItem Value="3" Text="Option C" />
</asp:DropDownList>
 When i bind data to it and i know it has to be value 2, how do make it selected?

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