What command line will create the user falco with home directory assigned to the group users as primary group?

What command line will create the user falco with home directory assigned to the group users as
primary group?

A.
useradd -g users falco

B.
useradd -f users falco

C.
useradd -m -g users falco

D.
add user falco@users

E.
add -user falco -group users