What does the phrase
The roots of education are bitter but the fruit is suit

"The root or education are bitter" meaning when you start to learn of a certain subject or start your learning all in all, it's hard, tedious, and an assortment of other difficulties.

then you would go on through learning as a tree would go through it's lifespan

"But the fruit is sweet" which means in the end, your work pays off through everything you know and can do with it. this relates to how a tree has the final product of fruits. fruiting is the last part of a tree's life before it starts all over (some trees, not all of course)

Ingrandire maybe, i’m italian but i don’t perfectly understood ur question

The correct answer is d. 6