If Statements and operators

Hi everyone. I wanted to know if there is a better way to do this:

if (var == 'A' || var == 'B' || var == 'C' || var == 'D')

I find it very annoying and repetitive to have to compare the same variable multiple times and have to write down the same thing over and over again.

I tried this out but apparently it doesn't work:

if (var == ('A' || 'B' || 'C' || 'D'))

I can’t think of anything else

Maybe

if( (var > 64) && (var < 69) )

if (var >= 'A' and var <= 'D') {
  switch ( var )
  {
    case 'A' ... 'D':
      Serial.println("Var!");
      break;

    default:;
      break;

  }