I would probably say that the author used diction to achieve some kind of effect in the first sentence.
A. The teacher stood at the door smiling brightly and welcoming each student to her classroom on the first day of school.
The author's diction, or word choice, in this sentence portrays the teacher as a nice, kind, caring person.
Answer:
NICKI MINAJ IS THE QUEEN OF RAP
Explanation:
B. A possessive noun should have its instead of it's (which is a contraction for it is).
For A. Diana is a singular noun and the apostrophe should come after the r instead of after the s.
For C. The duck would've dunked ITS instead of IT'S beak since it is possessive.
For D. You do not need to put an apostrophe since theirs is already a possessive noun.