Question

Which major accomplishments were achieved within the Persian Empire?

Answer 1

I believe it is A and B. I may not be correct, though.

I know C is not correct.

Answer 2

I believe the answer is:

built a vast network of roads

The vast network of roads is beneficial for the persian empire to be able to distribute the goods that they produce to other empire and obtain economic reward from it.

introduced architectural styles and farming techniques from other parts of the world

The persian empire at that time become the center of trades among 3 different continents. As the treding process occurs, culture and knowledges (such as agricultural styles and farming techniques)  were exchanged between traders.