Bash: Scripting - part 1- while getopts abcd opt

#!/bin/bash
#
while getopts abcd opt
do
        case "$opt" in
                a)
                        echo "Option: a" ;;
                b)
                        echo "Option: b" ;;
                c)
                        echo "Option: c" ;;
                d)
                        echo "Option: d" ;;
        esac
done






Results:
$ ./getopts11.sh -b
Option: b