If/else-if/else in Scheme/Lisp

I'm playing around with Scheme (though restricted to the lisp aspects for the assignment that I'm preparing for) and I'm trying to figure out how to perform an "if/else-if/else" using condin Scheme. How would I implement something like

public void check(char symbol)
{
    if(symbol == 'a')
    {
        System.out.println("a");
    }
    else if(symbol == 'b')
    {
        System.out.println("b");
    }
    else if (symbol == 'c')
    {
        System.out.println("c");
    }
    else
    {
        System.out.println("None of these");
    }
}

Off the top of my head I'd think it would be something like

(define (check symbol)
  (cond ((null? symbol) (display "null" ))
        ((equal? 'a lst) (display "a"))
        ((equal? 'b lst) (display "b"))
        ((equal? 'c lst) (display "c"))
        (else (display "none of these"))
        )
 )

This doesn't work however and I'm pretty stuck.. any help would be appreciated.