Match the following variables available to the user that are set internally by the shell, with their descriptions:
1.
$1 - $9 a. process ID of the shell
2.
$* b. the string containing all the arguments to the shell
3.
$? c. process ID of the last command run in the background
4.
$$ d. positional parameters
5.
$! e. exit status of the most recently executed command