Formal.
As far as I know, there is no such thing as either standard or practiced diction. Informal is the way you communicate with your friends, for instance, which is not how you would write a thesis paper, legal document, etc.
It is B: Education
:D
the teacher made this question easy so next time check your announcements ok? (im just assuming youre in k12)
Dear Dad,
When are you bringing the milk back from the store, its been twenty two years?
Love,
Son
