You are creating a Windows Forms application by using the .NET Framework 3.5. You plan to modify a list of orders within a DataGridView control in the application. You need to ensure that a value is required in the first column of the grid control. Which code segment should you use?

A.
private void dataGridOrders_CellValidated( object sender, DataGridViewCellEventArgs e)
{
if (e.ColumnIndex == 0)
{
var cellValue = dataGridOrders[e.ColumnIndex, e.RowIndex].Value;
if (cellValue == null || string.IsNullOrEmpty(cellValue.ToString()))
{
dataGridOrders.EndEdit();
}
}
}

B.
private void dataGridOrders_Validated( object sender, EventArgs e)
{
if (dataGridOrders.CurrentCell.ColumnIndex == 0)
{
var cellValue = dataGridOrders.Text;
if (cellValue == null || string.IsNullOrEmpty(cellValue.ToString()))
{
dataGridOrders.EndEdit();
}
}
}

C.
private void dataGridOrders_Validating( object sender, CancelEventArgs e)
{
if (dataGridOrders.CurrentCell.ColumnIndex == 0)
{
var cellValue = dataGridOrders.Text;
if (cellValue == null || string.IsNullOrEmpty(cellValue.ToString()))
{
e.Cancel = true;
}
}
}

D.
private void dataGridOrders_CellValidating( object sender, DataGridViewCellValidatingEventArgs e) {
if (e.ColumnIndex == 0) {
if (e.FormattedValue == null || string.IsNullOrEmpty(e.FormattedValue.ToString()))
{
e.Cancel = true;
}
}
}