code for check box with strike option.

You will need to use individual checkboxes to have control over each ones font separately; if you use the checkbox group you can only apply the font change to all the labels shown.  If they are separate, you can dump into a panel to gain the same effect as the checkbox group and you can dynamically create and add the checkboxes to the panel if need be.

To handle the issue of striking out the checkbox label, this will do it:

private void checkBox1_CheckedChanged(object sender, EventArgs e)
{
     Font startFont = checkBox1.Font;
     checkBox1.Font = new Font(startFont, startFont.Style ^ FontStyle.Strikeout);
}