Meaning that is displayed by [alternatives --config mta] is what?

Question

The following screen appears when run [alternatives --config mta].

There are 2 programs which provide 'mta'.

  Selection    Command
-----------------------------------------------
 + 1           /usr/sbin/sendmail.postfix
*  2           /usr/sbin/sendmail.sendmail

Enter to keep the current selection[+], or type selection number: 

1. What does asterisk(*) mean?
2. What does plus(+) mean?

Answer 1

The asterisk (`*) indicates the option that the alternatives software believes is "best" and would use if auto mode is selected.

Answer 2

In alternatives, each link has a priority which you set when you use alternatives --install or it is set automatically for you. The priority is used to choose the link when alternatives is in auto mode.

The asterisk indicates the link with the highest priority.