When you place a button named okButton on a Form in the IDE and double$-$click it$,$ what method header is generated automatically? $($Note that if you are using Visual Studio $2019,$ each method name will start with an uppercase letter.$)$

a$.$ public void okButton$\_$Click $($object sender$,$ EventArgs e$)$

b$.$ private void okButton$\_$Click $($object sender$,$ EventArgs e$)$

c$.$ static void okButton$\_$Click $($object sender$,$ EventArgs e$)$

d$.$ private int okButton$\_$Click $($object sender$,$ EventArgs e$)$