Which command can be used to create a new command that will monitor the contents of auth.log as they get added to the file?

a$.$

ln showauth$=$'tail $-$f $/$var$/$log$/$auth$.$log$\text{'}$

b$.$

create showauth$=$'tail $-$f $/$var$/$log$/$auth$.$log$\text{'}$

c$.$

new showauth as $$cat $-$f $/$var$/$log$/$auth$.$log$\text{'}$

d$.$

alias showauth$=$'tail $-$f $/$var$/$log$/$auth$.$log$\text{'}$