For a new portal to be developed for an apparel company, Simon writes an use case to 'order apparel'. While creating this use case he might observe that he has to first login into the system. But he realizes that order apparel is an observable user goal while as login to system is not $.$ So $\_\_\_\_\_\_\_\_\_\_\_\_$actors use the system to achieve an observable user goal.

Question $30$ options:

a$)$

Tertiary

b$)$

Primary

c$)$

None

d$)$

Secondary