1.Print Alphabets in the following pattern using C# string builder 
Ans:
 StringBuilder letters = new StringBuilder("ABCDEFGHIJKLMNOPQRSTUVWXYZ");StringBuilder result = new StringBuilder();
for (int i = 0; i <= letters.Length; i++)
{
for (int j = 0; j <i; j++)
{
result = result.Append(letters[j].ToString());
}
result = result.AppendLine();
}
Console.WriteLine(result);