Which line of code should you add?

You create an application by using the Microsoft .NET Framework 3.5 and Microsoft ADO.NET.

You write the following code segment.

DataTable dt = new DataTable("Customer");
dt.Columns.Add("ID", typeof(Int32));
dt.Columns.Add("State", typeof(String));
dt.Columns.Add("RegionCode", typeof(String));
dt.Rows.Add(1, "WA", "MT297EM");
dt.Rows.Add(2, "CA", "MT33SG");
dt.Rows.Add(3, "NY", "MT73229MP");

var query = from c in dt.AsEnumerable()
select c["RegionCode"];
foreach (string rNum in query)

You need to display only the digits from the RegionCode field.

Which line of code should you add?

A.
Console.WriteLine(rNum.Select(c => char.IsDigit(c)));

B.
Console.WriteLine(rNum.Select(c => char.IsDigit(c) c:”));

C.
Console.WriteLine(rNum.Select(delegate(char c) { return char.IsDigit(c); }));

D.
Console.WriteLine(rNum.Select(delegate(char c, int p) { return p.CompareTo(c); }));