What will be the output of the C#.NET code snippet given below?

char ch = Convert.ToChar ('a' | 'b' | 'c'); 
switch (ch)
{
    case 'A': 
    case 'a':
    Console.WriteLine ("case A | case a");
    break;
    
    case 'B': 
    case 'b':
    Console.WriteLine ("case B | case b");
    break;
    
    case 'C':
    case 'c':
    case 'D':
    case 'd':
    Console.WriteLine ("case D | case d");
    break;
}