When you do "scanf("%c", &a);" you save only one character, so you can't use "printf("%s", &a);" to display the character saved in "a", if you execute this code, a segfault might append. To display the caracter in "a", you have to use "printf("%c", a);".
public class GrossmontBank
//class variables (global - accessible throughout this class)
//scanner object to be used throughout
private static Scanner input = new Scanner(System.in);