$2.$Which of the following are $$mandatory guidance$$ in The IIA$$s IPPF?

I.$$Implementation Guides.

II$.$The Code of Ethics.

III.$$The Definition of Internal Auditing.

IV$.$ The Standards.

a$.$ I, II$,$ and IV$.$

b$.$ II and IV$.$

c$.$ II$,$ III, and IV$.$

d$.$ I, II$,$ III, and IV$.$