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;
}