Answer:
To contradict the message conveyed by the main plot
A subplot can focus on another aspect of the protagonist, or it can follow the story of another main character and his or her development. It can drive home theme and it can aid in world-building. Subplots will enrich your novel and make your story a more compelling read.
Jack and I - we
Books - it
Sister - she
You and Dave - they
Plane - it
Sunshine - it
Cheese - it
Cactus - it
Parents - they
Pamela - she
News - it
Scissors - they
Geese - they
Flowers - they
Piano - it
School - it
Daughter - she
Milk - it
Children - they
Sugar - it
Feet - they
Bicycle - it
Ann and Kate - they
Tennis - it
Son - he
Mice - they
Sky - it
Shop - it
Buses - they
Papers - they
Mr. Green - he
Brother-in-law - he
Picture - it
Friendship - it
Dolphin - it
The Ringgs family - they
I think it is D and A. I hope I helped, Please give me brainiest, with love- have a nice day- Emma
D tone is the answer hope it helps